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                                                                     EXHIBIT 4.6


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                            TELE-COMMUNICATIONS, INC.


                                       and


                          THE BANK OF NEW YORK, Trustee


                                ----------------



                          SECOND SUPPLEMENTAL INDENTURE
                          Dated as of February 25, 2000


              Supplement to Indenture Dated as of February 19, 1998
                               as supplemented by
             First Supplemental Indenture Dated as of March 9, 1999


                              --------------------



                          7.125% Senior Notes due 2028
                          6.375% Senior Notes due 2003




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     THIS SECOND SUPPLEMENTAL INDENTURE (this "Supplemental Indenture") is made
as of February 25, 2000, between TELE-COMMUNICATIONS, INC., a Delaware
corporation ("TCI" or, the "Company"), as successor issuer, and THE BANK OF NEW
YORK, a New York banking corporation (the "Trustee"), as trustee.


                                    RECITALS

     WHEREAS, TCI and the Trustee are parties to an Indenture, dated as of
February 19, 1998, as supplemented by a First Supplemental Indenture, dated as
of March 9, 1999 (collectively, the "Original Indenture"), pursuant to which the
Company issued (as successor issuer), and the Trustee authenticated and
delivered the following securities which are, as of the date hereof, currently
outstanding (collectively, the "Securities"):

(a) $300,000,000 aggregate principal amount of the Company's 7.125% Senior Notes
due 2028; and

(b) $750,000,000 aggregate principal amount of the Company's 6.375% Senior Notes
due 2003;

     WHEREAS, the Board of Directors of TCI has determined that it is in the
best interests of TCI to convert its corporate form from a Delaware corporation
to a Delaware limited liability company pursuant to Section 266 of the Delaware
General Corporation Law and Section 18-214 of the Delaware Limited Liability
Company Act (the "Conversion");

     WHEREAS, the Board of Directors of TCI has determined that it is advisable
to amend certain provisions of the Original Indenture which may affect the
Conversion;

     WHEREAS, the Original Indenture provides that the Company and the Trustee
may amend or supplement the Original Indenture or the Securities of any series
without notice to or consent of any Holder of Securities or coupons to make any
change that, in the opinion of the Board of Directors, does not materially
adversely affect the rights of any Securityholder or the Holder of any coupon;

     WHEREAS, the Board of Directors of TCI has determined that the amendments
to the Indenture contained in this Supplemental Indenture do not materially
adversely affect the rights of any Securityholder or the Holder of any coupon;
and

     WHEREAS, this Supplemental Indenture has been duly authorized by all
necessary action on the part of TCI.

     NOW, THEREFORE, TCI and the Trustee agree as follows for the equal and
ratable benefit of the Holders:


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                                    ARTICLE I

                           DEFINITIONS; INTERPRETATION

SECTION 1.1         Definitions. Capitalized terms that are defined in the
               preamble or the recitals hereto shall have such meanings
               throughout this Supplemental Indenture. Capitalized terms used
               but not defined in this Supplemental Indenture have the meanings
               assigned thereto in the Original Indenture. The meanings assigned
               to all defined terms used in this Supplemental Indenture shall be
               equally applicable to both the singular and plural forms of such
               defined terms. The term "Indenture" as used herein means the
               Original Indenture, as amended and supplemented by this
               Supplemental Indenture, or as otherwise supplemented or amended
               from time to time by one or more indentures supplemental thereto
               or hereto entered into pursuant to the applicable provisions of
               the Indenture.

SECTION 1.2         Interpretation. References in the Original Indenture
               (including references in the Original Indenture as amended or
               supplemented hereby) to "this Indenture" (and indirect references
               such as "hereunder," "herein" and "hereof") shall be deemed
               references to the Original Indenture as amended and supplemented
               hereby. All of the covenants, agreements and provisions of this
               Supplemental Indenture shall be deemed to be and construed as
               part of the Original Indenture to the same effect as if fully set
               forth therein and shall be fully enforceable in the manner
               provided in the Original Indenture. Except as otherwise provided
               in this Supplemental Indenture, all of the covenants, agreements
               and provisions of the Original Indenture shall remain in full
               force and effect.

                                   ARTICLE II

                                   AMENDMENTS

SECTION 2.1         Amendments. The following provisions of the Original
               Indenture are hereby amended, modified, supplemented or replaced
               as follows:

     (a)            The definition of "Board of Directors" contained in Article
               One, Section 1.01 of the Original Indenture is amended to read in
               its entirety as follows: "Board of Directors means the Board of
               Directors of the Company or any authorized committee thereof, or,
               if the Company is not a corporation, the equivalent decision
               making body thereof or authorized committee thereof."


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     (b)            The definition of "Officer" contained in Article One,
               Section 1.01 of the Original Indenture is amended to add the
               words "(if any)" after the words "Chairman of the Board."

     (c)            Article Four, Section 4.07 is hereby amended to replace the
               word "corporate" appearing in the heading to such section and as
               the second to the last word of such section with the word
               "legal."

     (d)            Article Five is hereby amended to replace the word
               "CORPORATION" appearing in the heading thereof with the word
               "ENTITY."

     (e)            Article Five, Section 5.01 is hereby amended to insert the
               words "or limited liability company" after each occurrence of the
               word "corporation."

     (f)            Article Five, Section 5.01 is also hereby amended to insert
               the following words as a new paragraph after the first paragraph
               thereof: "Nothing in this Indenture shall prohibit the Company
               from effecting a conversion pursuant to applicable law of the
               Company from a corporation into a limited liability company or
               from a limited liability company into a corporation, and any such
               conversion shall not be deemed to be a consolidation, merger or
               transfer subject to the requirements of the immediately preceding
               paragraph, provided, that such conversion by law shall not be
               deemed to affect any obligations or liabilities of the Company
               incurred prior to such conversion (including obligations or
               liabilities with respect to the Securities). Notice of any such
               conversion shall be promptly delivered to the Trustee."

     (g)            Article Ten, Section 10.15 is hereby amended to insert the
               words "or limited liability company" after the word "corporation"
               in clause (2) thereof.

                                   ARTICLE III

                                  MISCELLANEOUS

SECTION 3.1         Conflict with the TIA. If any provision of this Supplemental
               Indenture modifies or excludes any provision of the TIA that is
               required under such Act to be part of and govern the Indenture,
               the latter provision of the TIA shall control. If any provision
               hereof modifies or excludes any provision of the TIA that may be
               so modified or excluded, the latter provision


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               of the TIA shall be deemed to apply to this Supplemental
               Indenture, as so modified or excluded, as the case may be.

SECTION 3.2         Date and Time of Effectiveness. This Supplemental Indenture
               shall become a legally effective and binding instrument at and as
               of the date hereof.

SECTION 3.3         Securities Deemed Conformed. As of the date hereof, the
               provisions of each Security then outstanding shall be deemed to
               be conformed, without the necessity for any reissuance or
               exchange of such Security or any other action on the part of the
               Holders, TCI or the Trustee, so as to reflect this Supplemental
               Indenture.

SECTION 3.4         Successors. All agreements of TCI and the Trustee in this
               Supplemental Indenture and in the Indenture shall bind their
               respective successors.

SECTION 3.5         Benefits of Supplemental Indenture. Nothing in this
               Supplemental Indenture, express or implied, shall give to any
               person, other than the parties hereto and their successors
               hereunder, any Agent, Authenticating Agent and the Holders, any
               benefit or any legal or equitable right, remedy or claim under
               this Supplemental Indenture or the Indenture.

SECTION 3.6         Separability. In case any provision in this Supplemental
               Indenture, or in the Indenture, shall be invalid, illegal or
               unenforceable, the validity, legality and enforceability of the
               remaining provisions shall not in any way be affected or impaired
               thereby, it being intended that all of the provisions hereof
               shall be enforceable to the full extent permitted by law.

SECTION 3.7         Trustee Responsibility. The Trustee assumes no duties,
               responsibilities or liabilities by reason of this Supplemental
               Indenture other than as set forth in the Original Indenture. The
               Trustee assumes no responsibility for the correctness of the
               statements herein contained, which shall be taken as statements
               of TCI. This Supplemental Indenture is executed and accepted by
               the Trustee subject to all of the terms and conditions of its
               acceptance of the trust under the Original Indenture, as fully as
               if said terms and conditions were herein set forth in full.

SECTION 3.8         Headings. The Article and Section headings of this
               Supplemental Indenture have been inserted for convenience of
               reference only, are not to be considered a part of this
               Supplemental Indenture and shall in no way modify or restrict any
               of the terms or provisions hereof.


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SECTION 3.9         Counterparts. This Supplemental Indenture may be executed in
               counterparts, each of which shall for all purposes be deemed to
               be an original, and all such counterparts shall together
               constitute but one and the same instrument.

SECTION 3.10        Notices. The addresses for notices to the Company and the
               Trustee set forth in Section 11.02 of the Original Indenture
               shall be amended, without further action, to read in their
               entirety as follows:

               "If to the Company:

                       Tele-Communications, Inc.
                       9197 South Peoria Street
                       Englewood, Colorado 80112
                       Attention: Treasurer

               If to the Trustee:

                      The Bank of New York
                      101 Barclay Street, Floor 21W
                      New York, New York 10286"

SECTION 3.11        Governing Law. This Supplemental Indenture shall be governed
               by and construed in accordance with the internal laws of the
               State of New York.


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     IN WITNESS WHEREOF, the parties hereto have caused this Supplemental
Indenture to be duly executed as of the day and year first above written.



                                             TELE-COMMUNICATIONS, INC.

                                             By:
                                                --------------------------------
                                                 Name:
                                                 Title:


                                             THE BANK OF NEW YORK, as Trustee

                                             By:
                                                --------------------------------
                                                 Name:
                                                 Title:


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