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                                                                     Exhibit 4.3

                              CENTURY BANCORP, INC.

                                 2004 STOCK PLAN

1.       PURPOSE

         The purpose of the Century Bancorp, Inc. 2004 Stock Plan is to
encourage ownership of Class A common stock of the Company by directors,
officers and employees of the Company and its Affiliates and to provide
additional incentives for them to promote the success of the Company's business
through awards of or relating to shares of the Company's Class A common stock.
The 2004 Stock Plan is intended to be an incentive stock option plan within the
meaning of Section 422 of the Code, but not all Options granted hereunder are
required to be Incentive Options.

2.       DEFINITIONS

         As used in this Plan the following terms shall have the respective
meanings set out below, unless the context clearly requires otherwise:

         2.1.     Affiliate means any corporation, partnership, limited
liability company, business trust, or other entity controlling, controlled by or
under common control with the Company.

         2.2.     Award means any grant of Options, grant of Stock Appreciation
Rights or award of Restricted Stock pursuant to the Plan.

         2.3.     Award Agreement means an agreement between the Company and the
recipient of an Award, setting forth the terms and conditions of the Award.

         2.4.     Board means the Company's Board of Directors.

         2.5.     Change of Control means the occurrence of any of the
following:

                  (a)      a merger or consolidation of the Company with or into
another person or the sale, transfer or other disposition of all or
substantially all the Company's assets to one or more persons in a single
transaction or a series of related transactions, unless securities possessing
more than 50% of the total combined voting power of the survivor's or acquiror's
outstanding securities (or the securities of any parent thereof) are held by a
person or persons who held securities possessing more than 50% of the total
combined voting power of the Company's outstanding securities immediately prior
to that transaction, or

                  (b)      any person or group of persons (within the meaning of
Section 13(d)(3) of the Securities Exchange Act of 1934, as amended and in
effect from time to time), directly or indirectly acquires beneficial ownership
(determined pursuant to Securities and Exchange Commission Rule 13d-3) of
securities possessing more than 20% of the total combined voting power of the
Company's outstanding securities pursuant to a tender or exchange offer made
directly to the Company's stockholders that the Board does not recommend the
stockholders accept, other than (i) the Company or an Affiliate, (ii) an
employee benefit plan of the Company or any of its Affiliates, (iii) a trustee
or other fiduciary holding securities under an employee benefit

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plan of the Company or any of its Affiliates, or (iv) an underwriter
temporarily holding securities pursuant to an offering of such securities, or

                  (c)      over a period of 36 consecutive months or less, there
is a change in the composition of the Board such that a majority of the Board
members (rounded up to the next whole number, if a fraction) ceases, by reason
of one or more proxy contests for the election of Board members, to be composed
of individuals who either (i) have been Board members continuously since the
beginning of that period, or (ii) have been elected or nominated for election as
Board members during such period by at least a majority of the Board members
described in the preceding clause (i) who were still in office at the time that
election or nomination was approved by the Board; or

                  (d)      a majority of the Board votes in favor of a decision
that a Change in Control has occurred.

         2.5.     Class A Common Stock means Class A common stock, par value
$1.00 per share, of the Company.

         2.6.     Code means the Internal Revenue Code of 1986, as amended from
time to time, or any statute successor thereto, and any regulations issued from
time to time thereunder.

         2.7.     Company means Century Bancorp, Inc., a corporation organized
under the laws of the Commonwealth of Massachusetts.

         2.8.     Compensation Committee means the Compensation Committee of the
Board or any other committee of the Board to which the Board has delegated
responsibility for the administration of the Plan.

         2.9.     Grant Date means the date as of which an Award is granted.

         2.10.    Incentive Option means an Option which by its terms is to be
treated as an "incentive stock option" within the meaning of Section 422 of the
Code.

         2.11.    Market Value means the value of a share of Class A Common
Stock on any date as determined by the Compensation Committee.

         2.12.    Nonstatutory Option means any Option that is not an Incentive
Option.

         2.13.    Option means an option to purchase shares of Class A Common
Stock.

         2.14.    Optionee means a Participant to whom an Option shall have been
granted under the Plan.

         2.15.    Participant means any holder of an outstanding Award under the
Plan.

         2.16.    Plan means this 2004 Stock Plan of the Company, as amended
from time to time.

         2.17.    Restricted Stock means a grant or sale of shares of Class A
Common Stock to a Participant subject to a Risk of Forfeiture.

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         2.18.    Restriction Period means the period of time, established by
the Compensation Committee in connection with an Award of Restricted Stock,
during which the shares of Restricted Stock are subject to a Risk of Forfeiture
described in the applicable Award Agreement.

         2.19.    Risk of Forfeiture means a limitation on the right of the
Participant to retain Restricted Stock, including a right in the Company to
reacquire shares of Restricted Stock at less than their then Market Value,
arising because of the occurrence or non-occurrence of specified events or
conditions.

         2.20.    Stock Appreciation Right means a right to receive any excess
in the Market Value of shares of Class A Common Stock over a specified exercise
price.

         2.21.    Ten Percent Owner means a person who owns, or is deemed within
the meaning of Section 422(b)(6) of the Code to own, stock possessing more than
10% of the total combined voting power of all classes of stock of the Company
(or any Affiliate). Whether a person is a Ten Percent Owner shall be determined
with respect to each Option based on the facts existing immediately prior to the
Grant Date of that Option.

3.       TERM OF THE PLAN

         Unless the Plan shall have been earlier terminated by the Board, Awards
may be granted hereunder at any time in the period commencing on the approval of
the Plan by the Company's Class B stockholders and ending immediately prior to
the tenth anniversary of the earlier of the adoption of the Plan by the Board or
approval of the Plan by the Company's Class B stockholders. Awards granted
pursuant to the Plan within such period shall not expire solely by reason of the
termination of the Plan.

4.       STOCK SUBJECT TO THE PLAN

         At no time shall the number of shares of Class A Common Stock issued
pursuant to or subject to outstanding Awards granted under the Plan exceed
150,000 shares of Class A Common Stock, subject, however, to the provisions of
Section 10 of the Plan. For purposes of applying the foregoing limitation, if
any Option or Stock Appreciation Right expires, terminates or is cancelled for
any reason without having been exercised in full, the shares as to which the
Option or Stock Appreciation Right was not exercised shall again be available
for Awards thereafter to be granted under the Plan, and if any Restricted Stock
is forfeited, the shares so forfeited shall again be available for Awards
thereafter to be granted under the Plan. Shares of Class A Common Stock issued
pursuant to the Plan may be either authorized but unissued shares or shares held
by the Company in its treasury.

5.       ADMINISTRATION

         The Plan shall be administered by the Compensation Committee. Subject
to the provisions of the Plan, the Compensation Committee shall have complete
authority, in its discretion, to make or to select the manner of making all
necessary determinations with respect to each Award to be granted by the Company
under the Plan in addition to any other determination allowed the Compensation
Committee under the Plan including the director, employee or officer to receive
the Award. In making such determinations, the Compensation Committee may take
into account the nature of the services rendered by the respective employees,
officers, and directors, their present and potential contributions to the
success of the Company and its subsidiaries, and such other

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factors as the Compensation Committee in its discretion shall deem relevant.
Subject to the provisions of the Plan, the Compensation Committee shall also
have complete authority to interpret the Plan, to prescribe, amend and rescind
rules and regulations relating to it, to determine the terms and provisions of
the respective Award Agreements (which need not be identical), and to make all
other determinations necessary or advisable for the administration of the Plan.
The Compensation Committee's determinations made in good faith on matters
referred to in this Plan shall be conclusive. Without in any way limiting the
foregoing, the Compensation Committee shall at the time each Option is granted
designate such Option as either an Incentive Option or a Nonstatutory Option.

6.       ELIGIBILITY; TERMS; TERMINATION OF EMPLOYMENT; TRANSFERABILITY

         6.1.     Eligibility. Pursuant and subject to the terms of this Plan,
the Compensation Committee may grant such Awards as the Compensation Committee
shall in its discretion determine to any non-employee member of the Board or of
any board of directors (or similar governing authority) of any Affiliate or any
employee of or officer of one or more of the Company and its Affiliates.
However, only employees of the Company and of the parent or subsidiary
corporations of the Company, as defined in Sections 424(e) and (f),
respectively, of the Code, shall be eligible for the grant of Incentive Options.
In no event shall the number of shares of Class A Common Stock covered by Awards
granted to any one person in any one calendar year exceed 25,000 shares.

         6.2.     Terms. Each grant of an Award shall be subject to all
applicable terms and conditions of the Plan, and such other terms and
conditions, not inconsistent with the terms of the Plan, as the Compensation
Committee may prescribe. No prospective Participant shall have any rights with
respect to an Award unless and until the Participant has executed an agreement
evidencing the Award, delivered a fully executed copy thereof to the Company,
and otherwise complied with the applicable terms and conditions of the Award.

         6.3.     Termination of Employment or Association. Unless the
Compensation Committee shall provide otherwise with respect to any Award, if the
Participant's employment or other association with the Company and its
Affiliates ends for any reason, including because of the Participant's employer
ceasing to be an Affiliate, (a) any outstanding Option or Stock Appreciation
Right of the Participant shall cease to be exercisable in any respect not later
than three months following that event and, for the period it remains
exercisable following that event, shall be exercisable only to the extent
exercisable at the date of that event, and (b) any other outstanding Award of
the Participant shall immediately be forfeited or otherwise be subject to return
to or repurchase by the Company on the terms specified in the applicable Award
Agreement. Military or sick leave or other bona fide leave shall not be deemed a
termination of employment or other association, provided that it does not exceed
the longer of three months or the period during which the absent Participant's
reemployment rights, if any, are guaranteed by statute or by contract.

         6.4.     Limited Transferability of Awards. Except as otherwise
provided in this Section 6.4, Awards shall not be transferable, and no Award or
interest therein may be sold, transferred, pledged, assigned, or otherwise
alienated or hypothecated, other than by will or by the laws of descent and
distribution. All of a Participant's rights in any Award may be exercised during
the life of the Participant only by the Participant or the Participant's legal
representative. However, the Compensation Committee may, at or after the grant
of an Award of a Nonstatutory Option or shares of Restricted Stock, provide that
such Award may be transferred by the recipient to a family

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member; provided, however, that any such transfer is without payment of any
consideration whatever and that no transfer shall be valid unless first approved
by the Compensation Committee, acting in its sole discretion. For this purpose,
"family member" means any child, stepchild, grandchild, parent, stepparent,
spouse, former spouse, sibling, niece, nephew, mother-in-law, father-in-law,
son-in-law, daughter-in-law, brother-in-law, or sister-in-law, including
adoptive relationships, any person sharing the employee's household (other than
a tenant or employee), a trust in which the foregoing persons have more than
fifty percent of the beneficial interests, a foundation in which the foregoing
persons (or the Participant) control the management of assets, and any other
entity in which these persons (or the Participant) own more than fifty percent
of the voting interests.

7.       SPECIFIC TERMS OF OPTIONS

         7.1.     Date of Grant. The granting of an Option shall take place at
the time specified in the Award Agreement.

         7.2.     Exercise Price. The price at which shares may be acquired
under each Incentive Option and each Nonstatutory Option shall be not less than
100% of the Market Value of Class A Common Stock on the Grant Date, and the
price under each Incentive Option granted to a Ten Percent Owner shall be not
less than 110% of the Market Value of Class A Common Stock on the Grant Date

         7.3.     Option Period. No Incentive Option may be exercised on or
after the tenth anniversary of the Grant Date, or on or after the fifth
anniversary of the Grant Date if the Optionee is a Ten Percent Owner. The Option
period under each Nonstatutory Option shall not be so limited solely by reason
of this Section.

         7.4.     Exercisability. An Option may be immediately exercisable or
become exercisable in such installments, cumulative or non-cumulative, as the
Compensation Committee may determine. In the case of an Option not otherwise
immediately exercisable in full, the Compensation Committee may accelerate the
exercisability of such Option in whole or in part at any time, provided the
acceleration of the exercisability of any Incentive Option would not cause the
Option to fail to comply with the provisions of Section 422 of the Code.

         7.5.     Exercise of Option. An Option may be exercised by the Optionee
giving written notice to the Company, specifying the number of shares with
respect to which the Option is then being exercised. The notice shall be
accompanied by payment in the form of cash or certified or bank check payable to
the order of the Company in an amount equal to the exercise price of the shares
to be purchased or, subject to such conditions, if any, as the Compensation
Committee may deem necessary to avoid adverse accounting effects to the Company,
by delivery of that number of shares of Class A Common Stock having a Market
Value equal to the exercise price of the shares to be purchased. Receipt by the
Company of such notice and payment shall constitute the exercise of the Option.
Within 30 days thereafter but subject to the remaining provisions of the Plan,
the Company shall deliver or cause to be delivered to the Optionee or his agent
a certificate or certificates for the number of shares then being purchased.
Such shares shall be fully paid and nonassessable. Nothing herein shall be
construed to preclude the Company from participating in a so-called "cashless
exercise", provided the Optionee or other person exercising the Option and each
other party involved in any such exercise shall comply with such procedures, and
enter into such agreements, of indemnity or otherwise, as the Company shall
specify.

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         7.6.     Limit on Incentive Option Characterization. An Incentive
Option shall be considered to be an Incentive Option only to the extent that the
number of shares of Class A Common Stock for which the Option first becomes
exercisable in a calendar year do not have an aggregate Market Value (as of the
date of the grant of the Option) in excess of the "current limit". The current
limit for any Optionee for any calendar year shall be $100,000 minus the
aggregate Market Value at the date of grant of the number of shares of Class A
Common Stock available for purchase for the first time in the same year under
each other Incentive Option previously granted to the Optionee under the Plan
and under each other incentive stock option granted to the Optionee under any
other incentive stock option plan of the Company and its Affiliates. Any shares
of Class A Common Stock which would cause the foregoing limit to be violated
shall be deemed to have been granted under a separate Nonstatutory Option,
otherwise identical in its terms to those of the Incentive Option.

         7.7.     Notification of Disposition. Each person exercising any
Incentive Option granted under the Plan shall be deemed to have covenanted with
the Company to report to the Company any disposition of such shares prior to the
expiration of the holding periods specified by Section 422(a)(1) of the Code
and, if and to the extent that the realization of income in such a disposition
imposes upon the Company federal, state, local or other withholding tax
requirements, or any such withholding is required to secure for the Company an
otherwise available tax deduction, to remit to the Company an amount in cash
sufficient to satisfy those requirements.

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8.       STOCK APPRECIATION RIGHTS

         8.1.     Tandem or Stand-Alone. Stock Appreciation Rights may be
granted in tandem with an Option (at or, in the case of a Nonstatutory Option,
after the award of the Option) or alone and unrelated to an Option. Stock
Appreciation Rights in tandem with an Option shall terminate to the extent that
the related Option is exercised, and the related Option shall terminate to the
extent that the tandem Stock Appreciation Rights are exercised.

         8.2.     Exercise Price. Stock Appreciation Rights shall have an
exercise price of not less than the Market Value of the Stock on the date of
award, or in the case of Stock Appreciation Rights in tandem with Options, the
exercise price of the related Option.

9.       RESTRICTED STOCK.

         9.1.     Purchase Price. Shares of Restricted Stock shall be issued
under the Plan for such consideration, if any, in cash, property or services (or
any combination thereof) as determined by the Compensation Committee.

         9.2.     Issuance of Certificates. Each Participant receiving a
Restricted Stock Award, subject to Section 9.3, shall be issued a stock
certificate in respect of such shares of Restricted Stock. The certificate shall
be registered in the name of the Participant and, if applicable, shall bear an
appropriate legend referring to the terms, conditions, and restrictions
applicable to such Award.

         9.3.     Escrow of Shares. The Compensation Committee may require that
the stock certificates evidencing shares of Restricted Stock be held in custody
by a designated escrow agent (which may but need not be the Company) until the
restrictions thereon shall have lapsed, and that the Participant deliver a stock
power, endorsed in blank, relating to the Stock covered by the Award.

         9.4.     Restrictions and Restriction Period. During the Restriction
Period applicable to shares of Restricted Stock, such shares shall be subject to
limitations on transferability and a Risk of Forfeiture arising on the basis of
such conditions related to the performance of services, Company or Affiliate
performance or otherwise as the Compensation Committee may determine and provide
for in the applicable Award Agreement. Any such Risk of Forfeiture may be waived
or terminated, or the Restriction Period shortened, at any time by the
Compensation Committee on such basis as it deems appropriate.

         9.5.     Rights Pending Lapse of Risk of Forfeiture or Forfeiture of
Award. Except as otherwise provided in the Plan or the applicable Award
Agreement, at all times prior to lapse of any Risk of Forfeiture applicable to,
or forfeiture of, an Award of Restricted Stock, the Participant shall have all
of the rights of a stockholder of the Company, including the right to vote, and
the right to receive any dividends with respect to, the shares of Restricted
Stock. The Compensation Committee, as determined at the time of Award, may
permit or require the payment of cash dividends to be deferred and, if the
Compensation Committee so determines, reinvested in additional Restricted Stock
to the extent shares are available under Section 4.

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         9.6.     Lapse of Restrictions. If and when the Restriction Period
expires without a prior forfeiture of the Restricted Stock, the certificates for
such shares shall be delivered to the Participant promptly if not theretofore so
delivered.

10.      ADJUSTMENTS FOR CORPORATE TRANSACTIONS

         10.1.    Stock Dividend, Etc. In the event of any dividend on Class A
Common Stock payable in Class A Common Stock or any split-up or contraction in
the number of shares of Class A Common Stock after the date of an Award
Agreement, the remaining number of shares of Class A Common Stock subject to
that Award and the price to be paid for each share subject to the Award shall be
proportionately adjusted.

         10.2.    Stock Reclassification. In the event of any reclassification
or change of outstanding shares of Class A Common Stock, immediately thereafter
(and subject to further adjustment for subsequent events) any outstanding Award
shall thereafter relate to shares of stock or other securities equivalent in
kind and value to those shares which the Participant would have received if he
or she had held of record the full remaining number of shares of Class A Common
Stock subject to the Award immediately prior to such reclassification or change.

         10.3.    Consolidation or Merger. In case of any consolidation or
merger of the Company with or into another company or in case of any sale or
conveyance to another company or entity of the property of the Company as a
whole, (a) each outstanding Option and Stock Appreciation Right shall terminate
and, to the extent that the value of the shares of stock, other securities or
cash which a stockholder is entitled to receive for one share of Class A Common
Stock in connection with such transaction exceeds the exercise price, the
Participant shall be entitled to receive either cash or shares of stock or other
securities equivalent in kind to the cash, shares or other securities which a
holder would have received if he or she had fully exercised the Option or Stock
Appreciation Right and held the number of shares of the Class A Common Stock
issued upon such exercise, immediately prior to such consolidation, merger, sale
or conveyance, with a value equal to such excess amount multiplied by the number
of shares he or she would have received if he or she so exercised the Option or
Stock Appreciation Right at that time, and (b) the Risk of Forfeiture on shares
of Restricted Stock then subject to outstanding Awards shall lapse.

         10.4.    Change in Control. In the event of any Change in Control, each
outstanding Option and Stock Appreciation Right shall become immediately
exercisable and the Risk of Forfeiture on each share of Restricted Stock shall
lapse.

         10.5.    Related Matters. Any adjustment required by this Section 10
shall be determined and made by the Compensation Committee. No fraction of a
share shall be purchasable or deliverable upon exercise, but in the event any
adjustment hereunder of the number of shares covered by an Award shall cause
such number to include a fraction of a share, such number of shares shall be
adjusted to the nearest smaller whole number of shares. In the event of changes
in the outstanding Class A Common Stock by reason of any stock dividend,
split-up, contraction, reclassification, or change of outstanding shares of
Class A Common Stock of the nature contemplated by this Section 10, the number
of shares of Class A Common Stock available for the purposes of the Plan as
stated in Section 4 and the maximum size of Awards for any Participant as stated
in Section 6.1 shall be correspondingly adjusted.

11.      SETTLEMENT OF AWARDS

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         11.1.    Investment Representation. The Company shall be under no
obligation to issue any shares covered by any Award unless the shares to be
issued pursuant to Awards granted under the Plan have been effectively
registered under the Securities Act of 1933, as amended, or the Participant
shall have given a written representation to the Company which is satisfactory
in form and substance to its counsel and upon which the Company may reasonably
rely, that he or she is acquiring the shares for his or her own account for the
purpose of investment and not with a view to, or for sale in connection with,
the distribution of any such shares.

         11.2.    Registration. If the Company shall deem it necessary or
desirable to register under the Securities Act of 1933, as amended or other
applicable statutes any shares of Class A Common Stock issued or to be issued
pursuant to Awards granted under the Plan, or to qualify any such shares of
Class A Common Stock for exemption from the Securities Act of 1933, as amended
or other applicable statutes, then the Company shall take such action at its own
expense.

         11.3.    Certificate Legend. Each certificate for a share of Class A
Common Stock to be issued pursuant to Awards granted under the Plan may, in
addition to any other applicable restriction, bear a legend referring to the
investment representation made in accordance with Section 11.1 and to the fact
that no registration statement has been filed with the Securities and Exchange
Commission with respect to the shares of Class A Common Stock evidenced by the
certificate.

         11.4.    Tax Withholding. Whenever shares of Class A Common Stock are
issued or to be issued pursuant to Awards granted under the Plan, the Company
shall have the right to require the recipient to remit to the Company an amount
sufficient to satisfy federal, state, local or other withholding tax
requirements if, when, and to the extent required by law (whether so required to
secure for the Company an otherwise available tax deduction or otherwise) prior
to the delivery of any certificate or certificates for such shares. However, in
such cases, Participants may elect, subject to the approval of the Compensation
Committee, to satisfy the withholding requirement, in whole or in part, by
having the Company withhold shares to satisfy their tax obligations.
Participants may only elect to have Shares withheld having a Market Value on the
date the tax is to be determined equal to the minimum statutory total tax which
could be imposed on the transaction. All elections shall be irrevocable, made in
writing, signed by the Participant, and shall be subject to any restrictions or
limitations that the Compensation Committee, deems appropriate. The obligations
of the Company under the Plan shall be conditional on satisfaction of all such
withholding obligations and the Company shall, to the extent permitted by law,
have the right to deduct any such taxes from any payment of any kind otherwise
due to the recipient of an Award.

12.      LIMITATION OF RIGHTS IN STOCK; NO SPECIAL SERVICE RIGHTS

         A Participant shall not be deemed for any purpose to be a stockholder
of the Company with respect to any of the shares of Class A Common Stock
issuable pursuant to an Award, except to the extent that the Award shall have
been exercised with respect thereto and, in addition, a certificate shall have
been issued therefor and delivered to the Participant or his agent. Nothing
contained in the Plan or in any Award Agreement shall confer upon any recipient
of an Award any right with respect to the continuation of his or her employment
or other association with the Company (or any Affiliate), or interfere in any
way with the right of the Company (or any Affiliate), at any time to terminate
such employment agreement or to increase or decrease, or otherwise adjust, the
other terms and conditions of the recipient's employment or other association
with the Company and its Affiliates.

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13.      TERMINATION AND AMENDMENT OF THE PLAN

         The Board may at any time terminate the Plan or make such modifications
of the Plan as it shall deem advisable. No termination or amendment of the Plan
may, without the consent of any recipient of an Award granted hereunder,
adversely affect the rights of such recipient under that Award. The Compensation
Committee may amend the terms of any Award theretofore granted, prospectively or
retroactively, provided as amended the Award is consistent with the terms of the
Plan, but no such amendment shall impair the rights of the recipient of the
Award without his or her consent.

14.      GOVERNING LAW

         The Plan and all Award Agreements and actions taken thereunder shall be
governed, interpreted and enforced in accordance with the laws of the
Commonwealth of Massachusetts, without regard to the conflict of laws principles
thereof.

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