UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                                    Form 13F
                               Form 13F COVER PAGE
Report for the Calendar Year or Quarter Ended: 3/31/2011
Check here if Amendment []; Amendment Number:
                                               -------
This Amendment (Check only one.):               [] is a restatement.
                                                [] adds new holdings entries.

Institutional Investment Manager Filing this Report:


Name:      Ridgeback Capital Investments L.P.

Address:   430 Park Avenue, 12th Floor
           New York, New York 10022


Form 13F File Number: 28-12856


The institutional investment manager filing this report and the person by whom
it is signed hereby represent that the person signing the report is authorized
to submit it, that all information contained herein is true, correct and
complete, and that it is understood that all required items, statements,
schedules, lists, and tables, are considered integral parts of this form.

Persons Signing this Report on Behalf of Reporting Manager:

Name:   Ridgeback Capital Investments Ltd., as General Partner, by Bud Holman
Title:  Director
Phone:  (212) 808-7729

Signature,  Place,  and  Date  of  Signing:

/s/ Bud Holman                     New York, New York                 5/16/2011
---------------------------------  ---------------------------------  ----------
[Signature]                        [City, State]                      [Date]



Report  Type  (Check  only  one):

[X]     13F HOLDINGS REPORT. (Check here if all holdings of this reporting
        manager are reported in this report.)

[ ]     13F NOTICE. (Check here if no holdings reported are in this report,
        and all holdings are reported by other reporting manager(s).)

[ ]     13F COMBINATION REPORT. (Check here if a portion of the holdings for
        this reporting manager are reported in this report and a portion are
        reported by other reporting manager(s).)

List of Other Managers Reporting for this Manager:




                              Form 13F SUMMARY PAGE

Report Summary:

Number of Other Included Managers:                    2

Form 13F Information Table Entry Total:               9

Form 13F Information Table Value Total:  $      614,834
                                         --------------
                                         (In Thousands)


List of Other Included Managers:

Provide a numbered list of the name(s) and 13F file number(s) of all
institutional investment managers with respect to which this report is filed,
other than the manager filing this report.

No.   Form 13F File Number  Name

1     28-12280              Ridgeback Capital Management LP
----  --------------------  ----------------------------------------------------
2     28-12277              Ridgeback Capital Investments Ltd.
----  --------------------  ----------------------------------------------------






                                                  FORM 13F INFORMATION TABLE

           COLUMN 1                COLUMN 2    COLUMN 3  COLUMN 4      COLUMN 5        COLUMN 6  COLUMN 7        COLUMN 8
------------------------------- -------------- --------- -------- ------------------- ---------- -------- ----------------------
                                                          VALUE    SHRS OR   SH/ PUT/ INVESTMENT  OTHER      VOTING AUTHORITY
        NAME OF ISSUER          TITLE OF CLASS   CUSIP   (x$1000)  PRN AMT   PRN CALL DISCRETION MANAGERS SOLE SHARED    NONE
------------------------------- -------------- --------- -------- ---------- --- ---- ---------- -------- ---- ------ ----------
                                                                                     
Amgen Inc.                      Common Stock   031162100   50,778    950,000 SH       SOLE       1,2         0      0    950,000
BioMarin Pharmaceuticals Inc.   Common Stock   09061G101   60,312  2,400,000 SH       SOLE       1,2         0      0  2,400,000
InterMune Inc.                  Common Stock   45884X103   47,190  1,000,000 SH       SOLE       1,2         0      0  1,000,000
Ironwood Pharmaceuticals        Common Stock   46333X108  145,242 10,389,262 SH       SOLE       1,2         0      0 10,389,262
The Medicines Company           Common Stock   584688105   78,192  4,800,000 SH       SOLE       1,2         0      0  4,800,000
Onyx Pharmaceuticals, Inc.      Common Stock   683399109   57,076  1,622,400 SH       SOLE       1,2         0      0  1,622,400
Regeneron Pharmaceuticals, Inc. Common Stock   75886F107   85,386  1,900,000 SH       SOLE       1,2         0      0  1,900,000
Pharmasset, Inc.                Common Stock   71715N106   87,226  1,108,200 SH       SOLE       1,2         0      0  1,108,200
YM BioSciences Inc.             Common Stock   984238105    3,432  1,300,000 SH       SOLE       1,2         0      0  1,300,000