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                                                                     EXHIBIT 1.1

                                                                  Execution Copy

                      ORIGEN RESIDENTIAL SECURITIES, INC..

                           $156,187,000 (Approximate)

                      Origen Manufactured Housing Contract
                           Trust Notes, Series 2005-B

                             UNDERWRITING AGREEMENT

                                                              New York, New York
                                                                December 8, 2005

Citigroup Global Markets Inc.
390 Greenwich Street, 4th Floor
New York, New York 10013

Dear Sir or Madam:

          Origen Manufactured Housing Contract Trust 2005-B (the "Issuer"), a
Delaware statutory trust, proposes to issue Origen Manufactured Housing Contract
Trust Collateralized Notes, Series 2005-B (the "Notes"), under an Indenture (the
"Indenture") dated as of December 1, 2005 between the Issuer and JPMorgan Chase
Bank as indenture trustee (the "Indenture Trustee"). The Issuer was formed
pursuant to a Trust Agreement, dated as of December 1, 2005 (the "Trust
Agreement"), among Wilmington Trust Company, as owner trustee, JPMorgan Chase
Bank, as certificate paying agent and certificate registrar, and Origen
Residential Securities, Inc. (the "Company"), as depositor. The Company hereby
proposes to sell the Notes to you (the "Underwriter"). The Notes are designated
as (i) the Class A-1 Notes, the Class A-2 Notes, the Class A-3 Notes and the
Class A-4 Notes (collectively, the "Class A Notes"), and (ii) the Class M-1
Notes, the Class M-2 Notes and the Class B Notes (collectively, the "Mezzanine
Notes").

          Payments on the Notes will be secured by a trust estate consisting
primarily of a segregated pool (the "Contract Pool") of manufactured housing
installment sales contracts and installment loan agreements (the "Contracts").
Each Contract provides for an original term to maturity of not greater than 30
years. The Contracts will be acquired by the Company from Origen Securitization
Company, LLC (the "Seller") in exchange for immediately available funds
representing the purchase price. The Seller has acquired the Contracts from
Origen Financial L.L.C. (the "Originator" and, together with the Company and the
Seller, the "Origen Companies"; the Origen Companies also referred to herein
individually as an "Origen Company"). The Notes are described more fully in
Schedule I hereto. The Class A Notes and the Mezzanine Notes are more fully
discussed in a registration statement which the Company has furnished to you.
This is to confirm the arrangements with respect to your purchase of the Notes.

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          Capitalized terms used but not defined herein shall have the meanings
assigned thereto in Appendix A to the Indenture.

     1. Representations and Warranties: The Origen Companies represent and
warrant to, and agree with, the Underwriter that:

     (a) The Company has filed with the Securities and Exchange Commission (the
     "Commission") a registration statement on Form S-3 (the file number of
     which is set forth on Schedule A hereto), for the registration of the Notes
     under the Securities Act of 1933, as amended (the "1933 Act"), which
     registration statement has become effective and copies of which have
     heretofore been delivered to you. Such registration statement, as amended
     as of the date hereof, meets the requirements set forth in Rule
     415(a)(1)(vii) under the 1933 Act and complies in all other material
     respects with the 1933 Act and the rules and regulations thereunder. The
     Company proposes to file with the Commission pursuant to Rule 424 under the
     1933 Act a supplement to the form of prospectus included in such
     registration statement relating to the Notes and the plan of distribution
     thereof, and has previously advised you of all further information
     (financial and other) with respect to the Notes and the Contract Pool to be
     set forth therein. Such registration statement, including the exhibits
     thereto, as amended as of the date hereof, is hereinafter called the
     "Registration Statement"; the prospectus included in the Registration
     Statement after the Registration Statement, as amended, became effective,
     or as subsequently filed with the Commission pursuant to Rule 424 under the
     1933 Act, is hereinafter called the "Basic Prospectus"; the form of
     prospectus supplemented by the supplement to the form of prospectus
     relating to the Notes, in the form in which it shall be first filed with
     the Commission pursuant to Rule 424 (including the Basic Prospectus as so
     supplemented) is hereinafter called a "Final Prospectus." Any preliminary
     form of any Final Prospectus that has heretofore been filed pursuant to
     Rule 424 or, prior to the effective date of the Registration Statement,
     pursuant to Rule 402(a) or 424(a), is hereinafter called a "Preliminary
     Final Prospectus." Subject to the Underwriter's compliance with its
     obligations pursuant to Section 4(b), the Company shall file any
     Computational Materials and ABS Term Sheets (as each defined herein)
     provided to it by the Underwriter under Section 4(c)(iii), except to the
     extent of any information set forth therein that constitutes Collateral
     Information (as defined below), with the Commission on Form 8-K
     concurrently (to the extent practicable) with the filing of the Prospectus
     Supplement under Rule 424(b) under the 1933 Act on the business day
     immediately following the date that the Final Prospectus is dated (the
     "Final Prospectus Date"). As used herein, "Collateral Information" means
     information with respect to the characteristics of the Contracts and
     administrative and servicing fees, as provided by or on behalf of the
     Company to the Underwriter in final form and set forth in the Prospectus
     Supplement. The Company will file with the Commission within fifteen days
     of the issuance of the Notes a report on Form 8-K setting forth specific
     information concerning the Notes and the Contract Pool to the extent that
     such information is not set forth in the Final Prospectus.


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          The Company has prepared the following information (collectively, the
     "Time of Sale Information"): the Preliminary Final Prospectus dated
     November 30, 2005 and a Term Sheet dated November 30, 2005 (the "Term
     Sheet") to be used by the Underwriter at or prior to the time when sales to
     investors of the Notes are first made (the "Time of Sale"). If, subsequent
     to the date of this Agreement, the Company and the Underwriter have
     determined that such information included an untrue statement of material
     fact or omitted to state a material fact necessary in order to make the
     statements therein, in the light of the circumstances under which they were
     made, not misleading and have terminated their old purchase contracts and
     entered into new purchase contracts with purchasers of the Offered
     Certificates, then "Time of Sale Information" will refer to the information
     available to purchasers at the time of entry into the first such new
     purchase contract, including any information that corrects such material
     misstatements or omissions ("Corrective Information").

     (b) As of the date hereof, when the Preliminary Final Prospectus is first
     filed pursuant to Rule 424 under the 1933 Act, when the Final Prospectus is
     first filed pursuant to Rule 424 under the 1933 Act, when, prior to the
     Closing Date (as hereinafter defined), any amendment to the Registration
     Statement becomes effective, when any supplement to the Final Prospectus is
     filed with the Commission, and at the Closing Date, (i) the Registration
     Statement, as amended as of any such time, the Preliminary Final Prospectus
     as amended or supplemented as of any such time and the Final Prospectus, as
     amended or supplemented as of any such time, comply and will comply in all
     material respects with the applicable requirements of the 1933 Act and the
     rules and regulations thereunder, (ii) the Registration Statement, as
     amended as of any such time, does not and will not contain any untrue
     statement of material fact and does not and will not omit to state any
     material fact required to be stated therein or necessary in order to make
     the statements therein not misleading, (ii) the Preliminary Final
     Prospectus, as amended or supplemented as of any such time, does not and
     will not contain any untrue statement of a material fact and does not and
     will not omit to state a material fact necessary to make the statements
     therein, in the light of the circumstances under which they were made, not
     misleading; and (iii) the Final Prospectus, as amended or supplemented as
     of any such time, does not and will not contain any untrue statement of a
     material fact and does not and will not omit to state a material fact
     necessary to make the statements therein, in the light of the circumstances
     under which they were made, not misleading; provided, however, that the
     Origen Companies make no representations or warranties as to (i) the
     information contained in or omitted from the Registration Statement, the
     Preliminary Final Prospectus or Final Prospectus or any amendment thereof
     or supplement thereto in reliance upon and in conformity with the
     information furnished in writing to the Company by or on behalf of the
     Underwriter specifically for use in connection with the preparation of the
     Registration Statement, Preliminary Final Prospectus and the Final
     Prospectus as set forth on Exhibit A hereto (the "Underwriter's
     Information") or (ii) Derived Information in the Term Sheet.

          The Time of Sale Information, at the Time of Sale did not, and at the
     Closing Date will not, contain any untrue statement of a material fact or
     omit to state a material fact


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     necessary in order to make the statements therein, in the light of the
     circumstances under which they were made, not misleading; provided that the
     Company makes no representation and warranty with respect to Derived
     Information or any statements or omissions made in reliance upon and in
     conformity with information relating to the Underwriter furnished to the
     Company in writing by the Underwriter expressly for use in such Time of
     Sale Information.

          Other than the Time of Sale Information, the Final Prospectus and the
     Basic Prospectus, the Company (including its agents and representatives
     other than the Underwriters in their capacity as such) has not made, used,
     prepared, authorized, approved or referred to and will not make, use,
     prepare, authorize, approve or refer to any "written communication" (as
     defined in Rule 405 under the Securities Act) that constitutes an offer to
     sell or solicitation of an offer to buy the Notes.

     (c) Each of the Origen Companies has been duly incorporated and is validly
     existing as a corporation or limited liability company in good standing
     under the laws of the State of Delaware with full power and authority
     (corporate and other) to own its properties and conduct its business as now
     conducted by it and to enter into and perform its obligations under each of
     the following agreements to which it is a party: (i) this agreement, (ii)
     the Asset Purchase Agreement, dated as of December 1, 2005 (the "Purchase
     Agreement"), among the Company, the Originator and the Seller (iii) the
     Indenture, (iv) the Servicing Agreement, dated as of December 1, 2005 (the
     "Servicing Agreement"), among Origen Financial L.L.C., as servicer (the
     "Servicer"), Origen Servicing, Inc. (the "Subservicer"), the Issuer and the
     Indenture Trustee and (v) the Trust Agreement (this agreement, the Purchase
     Agreement the Servicing Agreement, the Indenture and the Trust Agreement
     individually, an "Agreement" and collectively, the "Agreements"); and none
     of the Origen Companies has received any notice of proceedings relating to
     the revocation or modification of any license, certificate, authority or
     permit applicable to its owning such properties or conducting such business
     which singly or in the aggregate, if the subject of an unfavorable
     decision, ruling or finding, would materially and adversely affect the
     conduct of the business, operations, financial condition or income of such
     Origen Company.

     (d) As of the date hereof, the time of sale, when the Final Prospectus is
     first filed pursuant to Rule 424 under the 1933 Act, when, prior to the
     Closing Date (as hereinafter defined), any amendment to the Registration
     Statement becomes effective, when any supplement to the Final Prospectus is
     filed with the Commission, and at the Closing Date, there has not and will
     not have been (i) any request by the Commission for any further amendment
     of the Registration Statement or the Final Prospectus or for any additional
     information, (ii) any issuance by the Commission of any stop order
     suspending the effectiveness of the Registration Statement or the
     institution or threatening of any proceeding for that purpose or (iii) any
     notification with respect to the suspension of the qualification of the
     Notes for sale in any jurisdiction or the initiation or threatening of any
     proceeding for such purpose.


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     (e) Each of the Agreements when executed and delivered as contemplated
     hereby and thereby will have been, duly authorized, executed and delivered
     by each Origen Company that is a party to such Agreement and each
     constitutes, or will constitute when so executed and delivered, a legal,
     valid and binding agreement of that Origen Company, enforceable against
     such Origen Company in accordance with its terms, except as enforceability
     may be limited by (i) bankruptcy, insolvency, liquidation, receivership,
     moratorium, reorganization or other similar laws affecting the enforcement
     of the rights of creditors, (ii) general principles of equity, whether
     enforcement is sought in a proceeding in equity or at law and (iii) public
     policy considerations underlying the securities laws, to the extent that
     such public policy considerations limit the enforceability of the
     provisions of such Agreement that purport to provide indemnification from
     securities law liabilities.

     (f) The Notes and each of the Agreements will conform in all material
     respects to the description thereof contained in the Time of Sale
     Information, the Final Prospectus, and the Notes, when duly and validly
     authorized, executed, authenticated and delivered in accordance with the
     Indenture and paid for by the Underwriter as provided herein, will be
     entitled to the benefits of the Indenture. On the Closing Date, the Trust
     Agreement will be effective to establish the Trust as a valid trust under
     the laws of the State of Delaware.

     (g) As of the Closing Date, the Contracts will meet the criteria for
     selection described in the Preliminary Final Prospectus and the Final
     Prospectus.

     (h) Neither the issuance and sale of the Notes, nor the execution and
     delivery by any of the Origen Companies of each Agreement to which it is a
     party, nor the consummation by any Origen Company of any of the
     transactions herein or therein contemplated, nor compliance by the Origen
     Companies with the provisions hereof or thereof, will conflict with or
     result in a breach of any term or provision of the certificate of
     incorporation, by-laws or operating agreement of any Origen Company or
     conflict with, result in a breach, violation or acceleration of or
     constitute a default under, the terms of any indenture or other agreement
     or instrument to which an Origen Company or any of its affiliates is a
     party or by which it or any of them is bound, or any statute, order or
     regulation applicable to such Origen Company or any of its affiliates of
     any court, regulatory body, administrative agency or governmental body
     having jurisdiction over the Company or any of its affiliates. None of the
     Origen Companies nor any of their affiliates is a party to, bound by or in
     breach or violation of any indenture or other agreement or instrument, or
     subject to or in violation of any statute, order or regulation of any
     court, regulatory body, administrative agency or governmental body having
     jurisdiction over it, which materially and adversely affects, or may in the
     future materially and adversely affect, (i) validity or enforceability of,
     or the ability of the Origen Companies to perform their obligations under,
     this Agreement, the Purchase Agreement or the Trust Agreement or (ii) the
     business, operations, financial conditions, properties or assets of the
     Origen Companies.

     (i) There are no actions or proceedings against, or investigations of, any
     Origen Company pending, or, to the knowledge of an Origen Company,
     threatened, before any


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     court, administrative agency or other tribunal (i) asserting the invalidity
     of any of the Agreements to which it is a party or the Notes, (ii) seeking
     to prevent the issuance of the Notes or the consummation of any of the
     transactions contemplated by any of the Agreements to which it is a party,
     (iii) that might materially and adversely affect the performance by an
     Origen Company of its obligations under, or the validity or enforceability
     of, any Agreement to which it is a party or the Notes, or (iv) seeking to
     affect adversely the federal income tax attributes of the Notes as
     described in the Time of Sale Information and the Final Prospectus.

     (j) Since the date as of which information is given in the Registration
     Statement, the Time of Sale Information or the Final Prospectus, there has
     not been any material adverse change in the business, operations, financial
     condition, properties or assets of any of the Origen Companies.

     (k) Any taxes, fees and other governmental charges payable by the Origen
     Companies in connection with the execution, delivery and issuance of this
     Agreement, the Purchase Agreement and the Trust Agreement or the execution,
     delivery and sale or transfer of the Notes have been or will be paid at or
     prior to the Closing Date.

     (l) None of the Issuer or the Origen Companies is, and the issuance and
     sale of the Notes in the manner contemplated by the Preliminary Final
     Prospectus and the Final Prospectus will not cause any of the Issuer or the
     Origen Companies to be, subject to registration or regulation as an
     investment company or affiliate of an investment company under the
     Investment Company Act of 1940, as amended (the "Investment Company Act").

     (m) Any certificate signed by an officer of the Issuer or any of the Origen
     Companies Company and delivered to an Underwriter or counsel for the
     Underwriters in connection with an offering of the Notes shall be deemed,
     and shall state that it is, a representation and warranty as to the matters
     covered thereby to each person to whom the representations and warranties
     in this Section 1 are made.

     (n) Since the date as of which information is given in the Preliminary
     Final Prospectus and the Final Prospectus, there has not been any material
     adverse change in the general affairs, management, financial condition, or
     results of operations of the Origen Companies, otherwise than as set forth
     or contemplated in the Preliminary Final Prospectus and the Final
     Prospectus, as supplemented or amended as of the Closing Date.

     (o) The Preliminary Final Prospectus was, and the Final Prospectus
     delivered to the Underwriter for use in connection with this offering will
     be, identical to the versions of the Preliminary Final Prospectus and Final
     Prospectus created to be transmitted to the Commission for filing via the
     Electronic Data Gathering Analysis and Retrieval System ("EDGAR"), except
     to the extent permitted by Regulation S-T.


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     (p) No Origen Company has taken, and will not take, directly or indirectly,
     any action which is designed to or which has constituted or which might
     reasonably be expected to cause or result in stabilization or manipulation
     of the price of any security of an Origen Company to facilitate the sale or
     resale of the Notes.

     (q) Neither an Origen Company nor any of its affiliates (i) is required to
     register as a "broker" or "dealer" in accordance with the provisions of the
     Exchange Act, or the rules and regulations thereunder (the "Exchange Act
     Regulations"), or (ii) directly, or indirectly through one or more
     intermediaries, controls or has any other association with (within the
     meaning of Article I of the Bylaws of the NASD) any member firm of the
     NASD.

     (r) No Origen Company has relied upon the Underwriter for any legal, tax or
     accounting advice in connection with the offering and sale of the Notes.

     (s) The Pool Information is accurate, true and correct.

     2. Purchase and Sale. Subject to the terms and conditions and in reliance
upon the representations and warranties set forth herein, the Company agrees to
sell to the Underwriter, and the Underwriter agrees to purchase from the Company
on the Closing Date, at the purchase price to public less the underwriting
discounts and commission for each class set forth in Schedule II hereto, the
Notes set forth in Schedule II hereto.

     3. Delivery and Payment. Delivery of and payment for the Notes shall be
made in the manner, on the date and at the time specified in Schedule I hereto
(or such later date not later than seven business days after such specified date
as the Underwriter shall designate), which date and time may be postponed by
agreement between the Underwriter and the Company or as provided in Section 9
hereof (such date and time of delivery and payment for the Notes being herein
called the "Closing Date"). Delivery of the Notes, as set forth on Schedule I
hereto, shall be made to the Underwriter against payment in same day Federal
funds by the Underwriter of the purchase price. The Notes shall be registered in
such names and in such authorized denominations as the Underwriter may request
not less than three full business days in advance of the Closing Date.

          The Company agrees to have the Notes available for inspection,
checking and packaging by the Underwriter in New York, New York, not later than
1:00 p.m. New York time on the business day prior to the Closing Date.

     4. Offering by Underwriter.

     (a) It is understood that the Underwriter proposes to offer the Notes for
     sale to the public as set forth in the Preliminary Final Prospectus and the
     Final Prospectus.


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     (b) It is understood that at or prior to the Time of Sale, the Underwriter
     will have provided to prospective investors the Time of Sale Information in
     connection with their offering of the Notes.

     (c) The Underwriter shall not enter into a Contract of Sale with any
     potential investor unless the Underwriter has conveyed the Preliminary
     Final Prospectus to such potential investor prior to such Contract of Sale.

     (d) The Underwriter agrees that:

          (i) Unless preceded or accompanied by a prospectus satisfying the
          requirements of Section 10(a) of the Securities Act, the Underwriter
          shall not convey or deliver any written communication to any person in
          connection with the initial offering of the Notes, unless such written
          communication (1) is made in reliance on Rule 134 under the Securities
          Act, (2) constitutes a prospectus satisfying the requirements of Rule
          430B under the Securities Act, or (3) is the Term Sheet.

          (ii) The Underwriter shall provide to the Company (in such written or
          electronic format as required by the Company) the Term Sheet that was
          sent to any prospective investors .

     The Underwriter may, or if requested by the Company shall, provide copies
     of the foregoing in a consolidated or aggregated form including all
     information described above.

     5. Agreements. The Origen Companies agree with the Underwriter that:

     (a) The Company will not file any amendment or supplement to the
     Registration Statement, the Preliminary Final Prospectus Supplement or the
     Final Prospectus, unless the Company has furnished to you a copy for your
     review prior to filing, and will not file or distribute any such proposed
     amendment or supplement to which you reasonably object. Subject to the
     foregoing sentence, the Company will cause the Preliminary Final Prospectus
     and the Final Prospectus to be transmitted to the Commission for filing
     within the time periods specified by Rule 424 under the 1933 Act and will
     file the Term Sheet provided to the Company with the Commission on Form 8-K
     no later than with the filing of each respective Final Prospectus under
     Rule 424(b) under the 1933 Act. The Company will promptly advise the
     Underwriter (i) when the Preliminary Final Prospectus and the Final
     Prospectus shall have been filed or transmitted to the Commission for
     filing pursuant to Rule 424, (ii) when any amendment to the Registration
     Statement shall have become effective, (iii) of any request by the
     Commission for any amendment of the Registration Statement or the Final
     Prospectus or for any additional information, (iv) of the issuance by the
     Commission of any stop order suspending the effectiveness of the
     Registration Statement or the institution or threatening of any proceeding
     for that purpose and (v) of


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     the receipt by the Company of any notification with respect to the
     suspension of the qualification of the Notes for sale in any jurisdiction
     or the initiation or threatening of any proceeding for such purpose. The
     Company will use its best efforts to prevent the issuance of any such stop
     order or suspension and, if issued, to obtain as soon as possible the
     withdrawal thereof.

     (b) If, at any time when a prospectus relating to the Notes is required to
     be delivered under the 1933 Act, any event occurs as a result of which any
     Preliminary Final Prospectus or Final Prospectus as then amended or
     supplemented would include any untrue statement of a material fact or omit
     to state any material fact necessary to make the statements therein in the
     light of the circumstances under which they were made not misleading, or if
     it shall be necessary to amend or supplement the Preliminary Final
     Prospectus or Final Prospectus to comply with the 1933 Act or the rules and
     regulations thereunder, the Company will promptly prepare and file with the
     Commission, subject to paragraph (a) of this Section 5, an amendment or
     supplement that will correct such statement or omission or an amendment
     that will effect such compliance and, if such amendment or supplement is
     required to be contained in a post-effective amendment of the Registration
     Statement, will use its best efforts to cause such amendment of the
     Registration Statement to be made effective as soon as possible.

     (c) The Company will (i) furnish to the Underwriter and counsel for the
     Underwriter, without charge, upon reasonable request, signed copies of the
     Registration Statement (including exhibits thereto) and each amendment
     thereto that shall become effective on or prior to the Closing Date and, so
     long as delivery of a prospectus by an Underwriter or dealer in connection
     with the Notes may be required by the 1933 Act, as many copies of the
     Preliminary Final Prospectus, the Final Prospectus and any amendments
     thereof and supplements thereto as the Underwriter may reasonably request,
     and (ii) file promptly all reports and any definitive proxy or information
     statements required to be filed by the Company with the Commission pursuant
     to Section 13(a), 13(c), 14 or 15(d) of the Securities Exchange Act of
     1934, as amended (the "1934 Act"), subsequent to the date of the Final
     Prospectus and for so long as the delivery of a prospectus by an
     Underwriter or dealer in connection with the Notes may be required under
     the 1933 Act.

     (d) The Company agrees that, so long as the Notes shall be outstanding, it
     will deliver to the Underwriter the annual statement as to compliance
     delivered to the Indenture Trustee pursuant to Section 3.15 of the
     Servicing Agreement and the annual statement of a firm of independent
     public accountants furnished to the Indenture Trustee pursuant to Section
     3.16 of the Servicing Agreement, as soon as such statements are furnished
     to the Company. The Company will request that the Servicer and the
     Indenture Trustee furnish to the Underwriter any monthly reports furnished
     to Noteholders pursuant to the Servicing Agreement and the Indenture.

     (e) The Company will furnish such information, execute such instruments and
     take such action, if any, as may be required to qualify the Notes for sale
     under the laws of such


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     jurisdictions as the Underwriter may designate and will maintain such
     qualifications in effect so long as required for the distribution of the
     Notes; provided, however, that the Company shall not be required to qualify
     to do business in any jurisdiction where it is not now so qualified.

     (f) The Origen Companies will pay all costs and expenses in connection with
     the transactions herein contemplated, including, but not limited to: the
     fees and disbursements of its counsel; the costs and expenses of printing
     (or otherwise reproducing) and delivering the Indenture, the Trust
     Agreement, the Servicing Agreement and the Notes; accounting fees and
     disbursements; the costs and expenses in connection with the qualification
     or exemption of the Notes under state securities or blue sky laws,
     including filing fees and reasonable fees and disbursements of counsel in
     connection with the preparation of any blue sky survey and in connection
     with any determination of the eligibility of the Notes for investment by
     institutional investors and the preparation of any legal investment survey;
     the expenses of printing any such blue sky survey and legal investment
     survey; the costs and expenses in connection with the preparation, printing
     and filing of the Registration Statement (including exhibits thereto), the
     Basic Prospectus, the Preliminary Final Prospectus and the Final
     Prospectus, the preparation and printing of this Agreement and the
     furnishing to the Underwriter of such copies of each Preliminary Final
     Prospectus and the Final Prospectus as the Underwriter may reasonably
     request, the fees of each nationally recognized statistical rating
     organization identified in the Final Prospectus (individually and
     collectively, the "Rating Agency") as having rated the Notes and the fees
     of counsel to the Underwriter. Except as provided in Section 7 hereof, the
     Underwriter shall be responsible for paying all costs and expenses incurred
     by them in connection with the offering of the Notes.

     6. Conditions to the Obligations of the Underwriter. The obligations of the
Underwriter to purchase the Notes shall be subject to the accuracy of the
representations and warranties on the part of the Origen Companies contained
herein as of the date hereof, as of the date of the effectiveness of any
amendment to the Registration Statement filed prior to the Closing Date and as
of the Closing Date, to the accuracy of the statements of the Origen Companies
made in any certificates pursuant to the provisions hereof, to the performance
by the Origen Companies of their obligations hereunder and to the following
additional conditions:

     (a) No stop order suspending the effectiveness of the Registration
     Statement, as amended from time to time, shall have been issued and not
     withdrawn and no proceedings for that purpose shall have been instituted or
     threatened; and the Final Prospectus shall have been filed or transmitted
     for filing with the Commission in accordance with Rule 424 under the 1933
     Act; the Prospectus and the Term Sheet shall have been timely filed with
     the Commission under the Securities Act and in accordance with Section 5(a)
     hereof; and all requests by the Commission for additional information shall
     have been complied with to the reasonable satisfaction of the Underwriter.


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     (b) The Company shall have delivered to you a certificate of the Company,
     signed by the President or a vice president or an assistant vice president
     of the Company and dated the Closing Date, to the effect that the signer of
     such certificate has carefully examined the Registration Statement, Time of
     Sale Information, Final Prospectus and this Agreement and that (i) the
     representations and warranties of the Company in this Agreement are true
     and correct in all material respects at and as of the Closing Date with the
     same effect as if made on the Closing Date, (ii) the Company has, in all
     material respects, complied with all the agreements and satisfied all the
     conditions on its part that are required by this Agreement to be performed
     or satisfied at or prior to the Closing Date, (iii) no stop order
     suspending the effectiveness of the Registration Statement has been issued
     and no proceedings for that purpose have been instituted or, to the
     Company's knowledge, threatened, (iv) nothing has come to the attention of
     such officer that would lead such officer to believe that the Time of Sale
     Information or Final Prospectus contains any untrue statement of a material
     fact or omits to state any material fact necessary in order to make the
     statements therein, in the light of the circumstances under which they were
     made, not misleading and (v) subsequent to the respective dates as of which
     information is given in the Final Prospectus, there has not been any
     material adverse change in the general affairs, capitalization, financial
     condition or results of operations of the Company.

     (c) The Underwriter shall have received from Hunton & Williams LLP, counsel
     for the Origen Companies, a favorable opinion or opinions, dated the
     Closing Date and satisfactory in form and substance to the Underwriter
     including without limitation a statement that nothing has come to such
     counsel's attention that would lead such counsel to believe that the
     Preliminary Final Prospectus and Final Prospectus, each as of its date, and
     on the Closing Date, contained or contain an untrue statement of a material
     fact or omitted or omit to state a material fact necessary in order to make
     the statements therein, in the light of the circumstances under which they
     were made, not misleading; it being understood that such counsel need
     express no view as to financial and statistical information contained
     therein.

     (d) The Underwriter shall have received from Deloitte & Touche, certified
     public accountants, a letter, dated the date hereof and satisfactory in
     form and substance to the Underwriter and counsel for the Underwriter, to
     the effect that they have performed certain specified procedures as a
     result of which they determined that certain information of an accounting,
     financial or statistical nature set forth in each respective Preliminary
     Final Prospectus and Final Prospectus under the captions "Summary of
     Prospectus Supplement--The Contracts," "Risk Factors" (to the extent of
     information regarding the Contracts therein) "The Contract Pool" "Yield on
     the Notes" and "Description of the Notes" agrees with the records of the
     Seller.

     (e) The Notes shall have been given the ratings set forth in Schedule I
     hereto by each Rating Agency.


                                                                              11

<PAGE>

     (f) The Underwriter shall have received, from counsel for the Indenture
     Trustee, a favorable opinion, dated the Closing Date, and in form and
     substance satisfactory to the Underwriter and its counsel, to the effect
     that the Indenture has been duly authorized, executed and delivered by the
     Indenture Trustee and constitutes the legal, valid and binding agreement of
     the Indenture Trustee, enforceable in accordance with its terms, except as
     enforceability may be limited by bankruptcy, insolvency, reorganization or
     other similar laws affecting the enforcement of creditors rights in general
     and by general principles of equity, regardless of whether such enforcement
     is considered in a proceeding in equity or at law, and as to such other
     matters as may be agreed upon by the Indenture Trustee and the Underwriter.

     (g) The Underwriter shall have received from the Seller, in form and
     substance satisfactory to counsel for the Underwriter:

          (i) An officer's certificate stating that on the Closing Date the
          representations and warranties of the Seller under the Purchase
          Agreement will be true and correct and no event has occurred that
          would constitute a default thereunder; and

          (ii) An officer's certificate relating to the Purchase Agreement and
          the obligations of the Seller thereunder, as Seller or otherwise,
          together with copies of the certificate of incorporation and by-laws
          of the Seller and a certificate of good standing of the Seller under
          the laws of the State of New York;

     (h) The Underwriter shall have received from the Originator in form and
     substance satisfactory to counsel for the Underwriter:

          (i) An officer's certificate stating that on the date each Contract is
          sold to the Seller (i) the representations and warranties of the
          Originator under the Purchase Agreement will be true and correct and
          no event has occurred that would constitute a default thereunder, (ii)
          nothing has come to the attention of such officer that would lead such
          officer to believe that the information set forth with respect to the
          Originator in the Prospectus Supplement and with respect to any
          private placement memorandum, any information of a comparable nature,
          contains any untrue statement of a material fact or omits to state any
          material fact necessary in order to make the statements therein, in
          the light of the circumstances under which they were made, not
          misleading and (iii) subsequent to the respective dates as of which
          information is given in the Prospectus Supplement and any private
          placement memorandum, there has not been any material adverse change
          in the general affairs, capitalization, financial condition or results
          of operations of the Originator; and

          (ii) An officer's certificate relating to the Purchase Agreement and
          the obligations of the Originator thereunder, as Originator or
          otherwise, together with


                                                                              12

<PAGE>

          copies of the operating agreement of the Originator and a certificate
          of good standing of the Originator under the laws of the State of
          Delaware.


                                                                              13

<PAGE>

     (i) The Underwriter shall have received from the Servicer, in form and
     substance satisfactory to counsel for the Underwriter.

          (i) An officer's certificate stating that on the Closing Date the
          representations and warranties of the Servicer contained in the
          Servicing Agreement will be true and correct and no event has occurred
          with respect to the Servicer that would constitute an Event of Default
          thereunder;

          (ii) An officer's certificate relating to the Servicing Agreement and
          the obligations of the Servicer thereunder, as Servicer or otherwise,
          and attached thereto the applicable resolutions of the board of
          directors of the Servicer, together with copies of the certificate of
          limited partnership and by-laws of the Servicer and a certificate of
          good standing of the Servicer issued by the State of Delaware; and

          (iii) The Underwriter shall have received from counsel to the
          Originator and the Servicer, a favorable opinion, dated the Closing
          Date and satisfactory in form and substance to counsel for the
          Underwriter.

     (j) The Underwriter shall have received copies of any opinions of counsel
     to the Company, the Seller, the Originator and the Servicer supplied to the
     Rating Agency or the Indenture Trustee relating to certain matters with
     respect to the Notes. Any such opinions shall be dated the Closing Date and
     addressed to the Underwriter or accompanied by the reliance letters to the
     Underwriter or shall state that the Underwriter may rely upon them.

     (k) All proceedings in connection with the transactions contemplated by
     this Agreement and all documents incident hereto shall be satisfactory in
     form and substance to the Underwriter and counsel for the Underwriter, and
     the Underwriter and counsel for the Underwriter shall have received such
     other information, certificates and documents as they may reasonably
     request.

     (l) All documents required under the Purchase Agreement have been provided
     to the appropriate parties.

          If any of the conditions specified in this Section 6 shall not have
been fulfilled in all material respects when and as provided in this Agreement,
if the Company is in breach of any covenants or agreements contained herein or
if any of the opinions and certificates mentioned above or elsewhere in this
Agreement shall not be in all material respects reasonably satisfactory in form
and substance to the Underwriter and counsel for the Underwriter, this Agreement
and all obligations of the Underwriter hereunder may be cancelled at, or at any
time prior to, the Closing Date by the Underwriter. Notice of such cancellation
shall be given to the Company in writing, or by telephone or telegraph confirmed
in writing.


                                                                              14

<PAGE>

     7. Reimbursement of Underwriter's Expenses. If the sale to the Underwriter
of the Notes as provided for herein is not consummated because any condition to
the obligations of the Underwriter set forth in Section 6 hereof is not
satisfied or because of any refusal, inability or failure on the part of the
Origen Companies to perform any agreement herein or comply with any provisions
hereof, other than by reason of default by the Underwriter, the Origen Companies
will reimburse the Underwriter upon demand for all out-of-pocket expenses,
including reasonable fees and disbursements of counsel, that shall have been
incurred by the Underwriter in connection with the proposed purchase and sale of
the Notes.

     8. Indemnification and Contribution. The Company agrees with the
Underwriter that:

     (a) The Origen Companies will, jointly and severally, indemnify and hold
     harmless the Underwriter, the directors, officers, employees and agents of
     the Underwriter, and each person who controls the Underwriter within the
     meaning of either the 1933 Act or the 1934 Act against any and all losses,
     claims, damages or liabilities, joint or several, to which they or any of
     them may become subject under the 1933 Act, the 1934 Act or other federal
     or state statutory law or regulation, at common law or otherwise, insofar
     as such losses, claims, damages or liabilities (or actions in respect
     thereof) arise out of or are based upon any untrue statement or alleged
     untrue statement of a material fact contained in (i) the Registration
     Statement, or in the Basic Prospectus, any Preliminary Final Prospectus or
     Final Prospectus, or in any amendment thereof or supplement thereto, or
     arise out of or are based upon the omission or alleged omission to state
     therein a material fact required to be stated therein or necessary to make
     the statements therein not misleading, or (ii) any Time of Sale Information
     or the omission or alleged omission to state a material fact required to
     make the statements therein, in light of the circumstances under which they
     were made, not misleading, which in each case was not corrected by
     Corrective Information subsequently supplied by the Depositor to the
     Underwriter resonably prior to the Time of Sale, and agrees to reimburse
     each such indemnified party, as incurred, for any legal or other expenses
     reasonably incurred by them in connection with investigating or defending
     any such loss, claim, damage, liability or action; provided, however, that
     the Origen Companies will not be liable in any such case to the extent that
     any such loss, claim, damage or liability arises out of or is based upon
     any such untrue statement or alleged untrue statement or omission or
     alleged omission made (i) therein in reliance upon and in conformity with
     any Underwriter's Information or (ii) in any Derived Information in the
     Term Sheet or required to be provided by the Underwriter to the Company
     pursuant to Section 4(b). This indemnity agreement will be in addition to
     any liability which the Company may otherwise have.

     (b) The Underwriter will indemnify and hold harmless the Company, its
     directors, each of the Company's officers who signs the Registration
     Statement, and each person, if any, who controls the Company within the
     meaning of either


                                                                              15

<PAGE>

     the 1933 Act or the 1934 Act, to the same extent as the foregoing indemnity
     from the Origen Companies to the Underwriter, but only with reference to
     (i) Derived Information or (ii) the Underwriter's Information. This
     indemnity agreement will be in addition to any liability that the
     Underwriter may otherwise have.

     (c) Promptly after receipt by an indemnified party under this Section 8 of
     notice of the commencement of any action, such indemnified party will, if a
     claim in respect thereof is to be made against the indemnifying party under
     this Section 8, notify the indemnifying party in writing of the
     commencement thereof; but the failure to so notify the indemnifying party
     (i) will not relieve it from liability under paragraph 8(a) or 8(b) above
     unless such failure results in the forfeiture by the indemnifying party of
     substantial rights and defenses and (ii) will not, in any event, relieve
     the indemnifying party from any obligations to any indemnified party other
     than the indemnification obligation provided in paragraph 8(a) or 8(b)
     above. The indemnifying party shall be entitled to appoint counsel of the
     indemnifying party's choice at the indemnifying party's expense to
     represent the indemnified party in any action for which indemnification is
     sought (in which case the indemnifying party shall not thereafter be
     responsible for the fees and expenses of any separate counsel retained by
     the indemnified party or parties except as set forth below); provided,
     however, that such counsel shall be satisfactory to the indemnified party.
     Notwithstanding the indemnifying party's election to appoint counsel to
     represent the indemnified party in an action, the indemnified party shall
     have the right to employ separate counsel (including local counsel), and
     the indemnifying party shall bear the reasonable fees, costs and expenses
     of such separate counsel if (i) the use of counsel chosen by the
     indemnifying party to represent the indemnified party would present such
     counsel with a conflict of interest, (ii) the actual or potential
     defendants in, or targets of, any such action include both the indemnified
     party and the indemnifying party and the indemnified party shall have
     reasonably concluded that there may be legal defenses available to it
     and/or other indemnified parties that are different from or additional to
     those available to the indemnifying party, (iii) the indemnifying party
     shall not have employed counsel satisfactory to the indemnified party to
     represent the indemnified party within a reasonable time after notice of
     the institution of such action or (iv) the indemnifying party shall
     authorize the indemnified party to employ separate counsel at the expense
     of the indemnifying party. An indemnifying party will not, without the
     prior written consent of the indemnified parties, settle or compromise or
     consent to the entry of any judgment with respect to any pending or
     threatened claim, action, suit or proceeding in respect of which
     indemnification or contribution may be sought hereunder (whether or not the
     indemnified parties are actual or potential parties to such claim or
     action) unless such settlement, compromise or consent (i) does not include
     a statement as to or admission of, fault, culpability or a failure to act
     by or on behalf of any such indemnified party, and (ii)includes an
     unconditional release of each indemnified party from all liability arising
     out of such claim, action, suit or proceeding.


                                                                              16

<PAGE>

     (d) In order to provide for just and equitable contribution in
     circumstances in which the indemnification provided for in paragraph (a) of
     this Section 8 is due in accordance with its terms but is for any reason
     held by a court to be unavailable from the Origen Companies on grounds of
     policy or otherwise, the Origen Companies and the Underwriter shall
     contribute to the aggregate losses, claims, damages and liabilities
     (including legal and other expenses reasonably incurred in connection with
     investigating or defending same) (collectively, "Losses") to which the
     Origen Companies and the Underwriter may be subject in such proportion as
     is appropriate to reflect the relative benefits received by the Origen
     Companies and the Underwriter from the offering of the Notes. If the
     allocation provided by the immediately preceding sentence is unavailable
     for any reason, the Origen Companies and the Underwriter shall contribute
     in such proportion as is appropriate to reflect not only such relative
     benefits but also the relative fault of the Origen Companies and the
     Underwriter in connection with the statements or omissions that resulted in
     such Losses as well as any other relevant equitable consideration. Benefits
     received by the Origen Companies shall be deemed to be equal to the total
     net proceeds from the offering (before deducting expenses) and benefits
     received by an Underwriter shall be deemed to total discounts and
     commissions received by the Underwriter. Relative fault shall be determined
     by reference to whether any alleged untrue statement or omission relates to
     the information provided by the Origen Companies or the Underwriter. The
     Origen Companies and the Underwriter agree that it would not be just and
     equitable if contribution were determined by pro rata allocation or any
     other method of allocation that does not take account of the equitable
     considerations referred to above. Notwithstanding the foregoing, in no
     event shall the Underwriter be required to contribute any amount in excess
     of the total discounts or commissions received by the Underwriter.
     Notwithstanding the provisions of this paragraph 8(d), no person guilty of
     fraudulent misrepresentation (within the meaning of Section 11(f) of the
     1933 Act) shall be entitled to contribution from any person who was not
     guilty of such fraudulent misrepresentation. For purposes of this Section
     8, each person, if any, who controls the Underwriter within the meaning of
     the 1933 Act or the 1934 Act and each director, officer, employee and agent
     of the Underwriter shall have the same rights to contribution as the
     Underwriter, and each person, if any, who controls the Origen Companies
     within the meaning of either the 1933 Act or the 1934 Act, each officer of
     an Origen Company who shall have signed the Registration Statement and each
     director of such Origen Company shall have the same rights to contribution
     as such Origen Company, subject in each case to the applicable terms and
     conditions of this paragraph 8(d).

     (e) For purposes hereof, as to the Underwriter, the term "Derived
     Information" means such information, if any, in the Term Sheet that is not
     contained in either (i) the Registration Statement, the Basic Prospectus,
     any Preliminary Final Prospectus or Final Prospectus or amendments or
     supplements thereto, taking into account information incorporated therein
     by reference (other than information incorporated by reference from the
     Term Sheet) or (ii) any Pool


                                                                              17

<PAGE>

     Information. "Derived Information" also excludes any omission or alleged
     omission or misstatement or alleged misstatement resulting from an error in
     any Issuer Information or the Pool Information. "Pool Information" means
     the information furnished to the Underwriter with respect to the
     characteristics of the Contracts. "Issuer Information" means such
     information as defined in Rule 433(h) under the Securities Act.

     9. [Reserved].

     10. Termination. This Agreement shall be subject to termination in the
absolute discretion of the Underwriter, by notice given to the Origen Companies
prior to delivery of and payment for all Notes if prior to such time (i) trading
in securities generally on the New York Stock Exchange shall have been suspended
or limited, or minimum prices shall have been established in such Exchange, (ii)
a banking moratorium shall have been declared by either federal or New York
State authorities or (iii) there shall have occurred any outbreak or material
escalation of hostilities, declaration by the United States of a national
emergency or war or other calamity or crisis, or there shall have occurred such
a material adverse change in general economic, political or financial conditions
(or the effect of international conditions on the financial markets of the
United States shall be such) which is material and adverse, and in the case of
any of the events specified in this clause (iii) such event makes it in the
judgment of the Underwriter, impractical or inadvisable to proceed with the
public offering or the delivery of the Notes on the terms and in the manner
contemplated in the Prospectus Supplement.

     11. Representations and Indemnities to Survive. The respective agreements,
representations, warranties, indemnities and other statements of the Company or
its officers and the Underwriter set forth in or made pursuant to this Agreement
will remain in full force and effect, regardless of any investigation made by or
on behalf of the Underwriter or the Company or any of the officers, directors or
controlling persons referred to in Section 8 hereof, and will survive delivery
of and payment for the Notes. The provisions of Sections 7 and 8 hereof shall
survive the termination or cancellation of this Agreement.

     12. Notices. All communications hereunder will be in writing and effective
only on receipt, and, if sent to the Underwriter, will be mailed, delivered or
telegraphed and confirmed to it at 390 Greenwich Street, 4th Floor, New York,
New York 10013, Attention: Managing Director, the Financial Institutions
Department; or, if sent to the Origen Companies, will be mailed, delivered or
telegraphed and confirmed to it at Origen Residential Securities, Inc. 27777
South Franklin Road Suite 1700, Southfield, Michigan 48034 Attention: Ron Klein,
Mark Landschulz and Andy Geater.

     13. Successors. This Agreement will inure to the benefit of and be binding
upon the parties hereto and their respective successors and the officers and
directors and controlling persons referred to in Section 8 hereof, and their
successors and assigns, and no other person will have any right or obligation
hereunder.


                                                                              18

<PAGE>

     14. Applicable Law. This Agreement will be governed by and construed in
accordance with the laws of the State of New York. This Agreement may be
executed in any number of counterparts, each of which shall for all purposes be
deemed to be an original and all of which shall together constitute but one and
the same instrument.


                                                                              19

<PAGE>

          If the foregoing is in accordance with your understanding of our
agreement, please sign and return to us a counterpart hereof, whereupon this
letter and your acceptance shall represent a binding agreement among the Origen
Companies and the Underwriter.

                                        Very truly yours,

                                        ORIGEN RESIDENTIAL SECURITIES, INC.


                                        By: /s/ R. Klein
                                            ------------------------------------
                                        Name: R. Klein
                                        Title: CEO


                                        ORIGEN SECURITIZATION COMPANY, LLC


                                        By: /s/ R. Klein
                                            ------------------------------------
                                        Name: R. Klein
                                        Title: CEO


                                        ORIGEN FINANCIAL L.L.C.


                                        By: /s/ R. Klein
                                            ------------------------------------
                                        Name: R. Klein
                                        Title: CEO

The foregoing Agreement is hereby
confirmed and accepted as of the date
first above written.

CITIGROUP GLOBAL MARKETS INC.


By: /s/ Paul G. Humphrey
    ---------------------------------
Name: Paul G. Humphrey
Title: Director


                                                                              20

<PAGE>

                                   SCHEDULE I

Underwriting Agreement, dated December 08, 2005

As used in this Agreement, the term "Registration Statement" refers to
registration statement No. 333-117573 filed by the Company on Form S-3 and
declared effective on August 16, 2004, as amended to date. The term "Basic
Prospectus" refers to the form of Prospectus filed with the Commission pursuant
to Rule 424 under the 1933 Act after the Registration Statement became
effective.

Title and Description of Notes: Origen Manufactured Housing Contract Trust
Collateralized Notes, Series 2005-B.

Initial aggregate principal balance of the Notes: $156,187,000 (Approximate)

<TABLE>
<CAPTION>
Class Designation   Initial Note Principal Balance (1)   Note Rate    S&P    Moody's
-----------------   ----------------------------------   ---------   -----   -------
<S>                 <C>                                  <C>         <C>     <C>
Class A-1                      $40,692,000                 5.250%     Aaa      AAA
Class A-2                      $39,295,000                 5.247%     Aaa      AAA
Class A-3                      $13,428,000                 5.605%     Aaa      AAA
Class A-4                      $19,897,000                 5.910%     Aaa      AAA
Class M-1                      $15,750,000                 5.990%     Aa2       AA
Class M-2                      $11,375,000                 6.480%      A2       A
Class B-1                      $12,250,000                 7.200%     Baa2     BBB
Class B-2                      $ 3,500,000                 7.200%     Baa3     N/R
</TABLE>

(1)  Approximate.

(2)  Subject to a rate cap as described in the Indenture.

Closing Time, Date and Location: 10:00 AM. on December 15, 2005 at the offices
of Hunton & Williams LLP, Riverfront Plaza- East Tower, 951 East Byrd Street,
Richmond, Virginia, 23219-4074 and denominations as the Underwriter may direct
in accordance with the Underwriting Agreement.


                                                                              21

<PAGE>

                                   SCHEDULE II

<TABLE>
<CAPTION>
                                                         Underwriting Discount
  Class     Principal Amount (1)   Price to Public (2)       and Commission      Proceeds to Depositor
  -----     --------------------   -------------------   ---------------------   ---------------------
<S>         <C>                    <C>                   <C>                     <C>
Class A-1        $40,692,000              5.250%                99.993%                  0.350%
Class A-2        $39,295,000              5.247%                99.998%                  0.350%
Class A-3        $13,428,000              5.605%                99.990%                  0.350%
Class A-4        $19,897,000              5.910%                99.980%                  0.350%
Class M-1        $15,750,000              5.990%                99.953%                  0.350%
Class M-2        $11,375,000              6.480%                99.948%                  0.350%
Class B-1        $12,250,000              7.200%                95.814%                  0.350%
Class B-2        $ 3,500,000              7.200%                89.758%                  0.350%
</TABLE>

(1)  Approximate.

(2)  Plus accrued interest from December 1, 2005


                                                                              22