The Securities and Exchange Commission has not necessarily reviewed the information in this filing and has not determined if it is accurate and complete.
The reader should not assume that the information is accurate and complete.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
FORM 13F

FORM 13F COVER PAGE

OMB APPROVAL
OMB Number: 3235-0006
Expires: July 31, 2015
Estimated average burden
hours per response: 23.8

Report for the Calendar Year or Quarter Ended: 06-30-2018
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: DEERFIELD MANAGEMENT COMPANY, L.P. (SERIES C)
Address: 780 THIRD AVENUE, 37TH FLOOR
NEW YORK , NY10017
Form 13F File Number: 028-05366

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.

Person Signing this Report on Behalf of Reporting Manager:
Name: James E. Flynn
Title: Managing Member
Phone: 212-551-1600
Signature, Place, and Date of Signing:
James E. Flynn New York , NY 08-14-2018
[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).)
Form 13F Summary Page
Report Summary:
Number of Other Included Managers: 1
Form 13F Information Table Entry Total: 114
Form 13F Information Table Value Total: 2,847,622
(thousands)
List of Other Managers Reporting for this Manager:
[If there are no entries in this list, omit this section.]
Form 13F File Number Name
028-11827 Flynn Management LLC

List of Other Included Managers:
Provide a numbered list of the name(s) and Form 13F file number(s) of all institutional investment managers with respect to which this report is filed, other than the manager filing this report.
[If there are no entries in this list, state “NONE” and omit the column headings and list entries.]
No. Form 13F File Number Name
1 028-11827 Flynn Management LLC


SEC FORM 13F-HR

The Securities and Exchange Commission has not necessarily reviewed the information in this filing and has not determined if it is accurate and complete.
The reader should not assume that the information is accurate and complete.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
FORM 13F

FORM 13F INFORMATION TABLE

OMB APPROVAL
OMB Number: 3235-0006
Expires: July 31, 2015
Estimated average burden
hours per response: 23.8

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 MANAGER SOLE SHARED NONE
AAC HLDGS INC COM 000307108 17,372 1,853,998 SH DFND 01 1,853,998 0 0
ACADIA HEALTHCARE COMPANY IN COM 00404A109 30,315 741,016 SH DFND 01 741,016 0 0
ACCELERON PHARMA INC COM 00434H108 54,672 1,126,800 SH DFND 01 1,126,800 0 0
ACLARIS THERAPEUTICS INC COM 00461U105 54,832 2,745,705 SH DFND 01 2,745,705 0 0
AEGERION PHARMACEUTICALS INC NOTE 2.000% 8/1 00767EAB8 10,707 16,600,000 PRN DFND 01 16,600,000 0 0
AERIE PHARMACEUTICALS INC COM 00771V108 32,698 484,055 SH DFND 01 484,055 0 0
AETNA INC NEW COM 00817Y108 42,022 229,000 SH DFND 01 229,000 0 0
AGIOS PHARMACEUTICALS INC COM 00847X104 29,481 350,000 SH DFND 01 350,000 0 0
AIMMUNE THERAPEUTICS INC COM 00900T107 18,097 673,000 SH DFND 01 673,000 0 0
ALBIREO PHARMA INC COM 01345P106 4,260 120,000 SH DFND 01 120,000 0 0
ALIMERA SCIENCES INC COM 016259103 5,922 6,052,935 SH DFND 01 6,052,935 0 0
ALNYLAM PHARMACEUTICALS INC COM 02043Q107 14,380 146,000 SH DFND 01 146,000 0 0
ALPINE IMMUNE SCIENCES INC COM 02083G100 6,912 913,100 SH DFND 01 913,100 0 0
ANAPTYSBIO INC COM 032724106 39,995 562,989 SH DFND 01 562,989 0 0
ANTHEM INC COM 036752103 45,464 191,000 SH DFND 01 191,000 0 0
ARALEZ PHARMACEUTICALS INC COM 03852X100 576 1,644,583 SH DFND 01 1,644,583 0 0
ARDELYX INC COM 039697107 12,920 3,491,922 SH DFND 01 3,491,922 0 0
ARENA PHARMACEUTICALS INC COM NEW 040047607 17,361 398,194 SH DFND 01 398,194 0 0
ARGENX SE SPONSORED ADR 04016X101 37,041 447,029 SH DFND 01 447,029 0 0
ASCENDIS PHARMA A S SPONSORED ADR 04351P101 32,094 482,467 SH DFND 01 482,467 0 0
AUDENTES THERAPEUTICS INC COM 05070R104 40,061 1,048,430 SH DFND 01 1,048,430 0 0
AUTOLUS THERAPEUTICS PLC SPON ADS 05280R100 6,698 250,000 SH DFND 01 250,000 0 0
AVADEL PHARMACEUTICALS PLC SPONSORED ADR 05337M104 16,687 2,722,241 SH DFND 01 2,722,241 0 0
AVROBIO INC COM 05455M100 5,712 200,000 SH DFND 01 200,000 0 0
BIOCRYST PHARMACEUTICALS COM 09058V103 34,744 6,063,496 SH DFND 01 6,063,496 0 0
BIOHAVEN PHARMACTL HLDG CO L COM G11196105 15,729 398,000 SH DFND 01 398,000 0 0
BIOSCRIP INC COM 09069N108 6,842 2,335,000 SH DFND 01 2,335,000 0 0
BLUEBIRD BIO INC COM 09609G100 17,735 113,000 SH DFND 01 113,000 0 0
BLUEPRINT MEDICINES CORP COM 09627Y109 30,150 474,950 SH DFND 01 474,950 0 0
BROOKDALE SR LIVING INC COM 112463104 20,959 2,305,773 SH DFND 01 2,305,773 0 0
CENTENE CORP DEL COM 15135B101 39,986 324,536 SH DFND 01 324,536 0 0
CVS HEALTH CORP COM 126650100 35,393 550,000 SH DFND 01 550,000 0 0
CVS HEALTH CORP COM 126650100 36,474 566,800 SH Call DFND 01 566,800 0 0
CYMABAY THERAPEUTICS INC COM 23257D103 18,025 1,343,181 SH DFND 01 1,343,181 0 0
CYTOMX THERAPEUTICS INC COM 23284F105 16,687 729,948 SH DFND 01 729,948 0 0
DBV TECHNOLOGIES S A SPONSORED ADR 23306J101 55,941 2,900,000 SH DFND 01 2,900,000 0 0
DEPOMED INC NOTE 2.500% 9/0 249908AA2 21,952 27,019,000 PRN DFND 01 27,019,000 0 0
DEXCOM INC COM 252131107 15,688 165,175 SH DFND 01 165,175 0 0
DFB HEALTHCARE ACQUISTION CO UNIT 01/30/2023 23291E208 25,375 2,500,000 SH DFND 01 2,500,000 0 0
EDITAS MEDICINE INC COM 28106W103 41,521 1,158,841 SH DFND 01 1,158,841 0 0
EHEALTH INC COM 28238P109 24,419 1,104,952 SH DFND 01 1,104,952 0 0
EIDOS THERAPEUTICS INC COM 28249H104 6,586 323,807 SH DFND 01 323,807 0 0
ELECTROCORE INC COM 28531P103 7,017 425,000 SH DFND 01 425,000 0 0
ENDOCYTE INC COM 29269A102 32,075 2,324,299 SH DFND 01 2,324,299 0 0
ENDOLOGIX INC NOTE 3.250%11/0 29266SAB2 38,243 40,500,000 PRN DFND 01 40,500,000 0 0
EPIZYME INC COM 29428V104 22,208 1,639,000 SH DFND 01 1,639,000 0 0
EYENOVIA INC COM 30234E104 1,890 300,000 SH DFND 01 300,000 0 0
FOAMIX PHARMACEUTICALS LTD SHS M46135105 3,377 674,002 SH DFND 01 674,002 0 0
FORTY SEVEN INC COM 34983P104 9,600 600,000 SH DFND 01 600,000 0 0
G1 THERAPEUTICS INC COM 3621LQ109 12,473 287,000 SH DFND 01 287,000 0 0
GALAPAGOS NV SPON ADR 36315X101 15,210 165,000 SH DFND 01 165,000 0 0
GLAUKOS CORP COM 377322102 30,652 754,222 SH DFND 01 754,222 0 0
GW PHARMACEUTICALS PLC ADS 36197T103 32,513 233,000 SH DFND 01 233,000 0 0
HOMOLOGY MEDICINES INC COM 438083107 106,632 5,227,035 SH DFND 01 5,227,035 0 0
HORIZON PHARMA INVT LTD NOTE 2.500% 3/1 44052TAB7 94,914 99,100,000 PRN DFND 01 99,100,000 0 0
HORIZON PHARMA PLC SHS G4617B105 109,460 6,609,894 SH DFND 01 6,609,894 0 0
IGI LABORATORIES INC NOTE 3.750%12/1 449575AB5 3,476 3,733,000 PRN DFND 01 3,733,000 0 0
IMMUNOMEDICS INC COM 452907108 26,624 1,124,800 SH DFND 01 1,124,800 0 0
INTERCEPT PHARMACEUTICALS IN NOTE 3.250% 7/0 45845PAA6 31,598 36,000,000 PRN DFND 01 36,000,000 0 0
INTERSECT ENT INC COM 46071F103 38,199 1,020,000 SH DFND 01 1,020,000 0 0
INVITAE CORP COM 46185L103 13,978 1,901,788 SH DFND 01 1,901,788 0 0
INVUITY INC COM NEW 46187J205 9,114 2,336,889 SH DFND 01 2,336,889 0 0
K2M GROUP HLDGS INC NOTE 4.125% 8/1 48273JAB3 26,036 20,000,000 PRN DFND 01 20,000,000 0 0
KEMPHARM INC NOTE 5.500% 2/0 488445AB3 55,438 75,000,000 PRN DFND 01 75,000,000 0 0
KINIKSA PHARMACEUTICALS LTD COM CL A G5269C101 21,287 1,226,890 SH DFND 01 1,226,890 0 0
LANNET INC COM 516012101 24,498 1,801,353 SH DFND 01 1,801,353 0 0
MALLINCKRODT PUB LTD CO SHS G5785G107 130,401 6,988,248 SH DFND 01 6,988,248 0 0
MANNKIND CORP COM NEW 56400P706 2,771 1,458,537 SH DFND 01 1,458,537 0 0
MELINTA THERAPEUTICS INC COM 58549G100 25,373 3,995,806 SH DFND 01 3,995,806 0 0
MIRATI THERAPEUTICS INC COM 60468T105 64,108 1,300,365 SH DFND 01 1,300,365 0 0
MOLINA HEALTHCARE INC COM 60855R100 16,454 168,000 SH DFND 01 168,000 0 0
MORPHOSYS AG SPONSORED ADS 617760202 18,204 600,000 SH DFND 01 600,000 0 0
MYLAN N V SHS EURO N59465109 62,960 1,742,111 SH DFND 01 1,742,111 0 0
MYOKARDIA INC COM 62857M105 57,544 1,159,000 SH DFND 01 1,159,000 0 0
NATERA INC COM 632307104 20,341 1,080,829 SH DFND 01 1,080,829 0 0
NEOS THERAPEUTICS INC COM 64052L106 1,458 233,332 SH DFND 01 233,332 0 0
NEURONETICS INC COM 64131A105 3,326 125,000 SH DFND 01 125,000 0 0
NEVRO CORP NOTE 1.750% 6/0 64157FAA1 29,913 27,600,000 PRN DFND 01 27,600,000 0 0
NUVASIVE INC NOTE 2.250% 3/1 670704AG0 7,591 7,000,000 PRN DFND 01 7,000,000 0 0
NUVECTRA CORP COM 67075N108 2,689 131,000 SH DFND 01 131,000 0 0
ORTHOPEDIATRICS CORP COM 68752L100 2,152 80,783 SH DFND 01 80,783 0 0
OXFORD IMMUNOTEC GLOBAL PLC ORD SHS G6855A103 16,899 1,311,000 SH DFND 01 1,311,000 0 0
PFENEX INC COM 717071104 6,112 1,129,684 SH DFND 01 1,129,684 0 0
PORTOLA PHARMACEUTICALS INC COM 737010108 54,639 1,446,633 SH DFND 01 1,446,633 0 0
PROTEON THERAPEUTICS INC COM 74371L109 3,001 1,224,899 SH DFND 01 1,224,899 0 0
PROTHENA CORP PLC SHS G72800108 9,160 628,262 SH DFND 01 628,262 0 0
RA PHARMACEUTICALS INC COM 74933V108 3,808 382,700 SH DFND 01 382,700 0 0
RADIUS HEALTH INC NOTE 3.000% 9/0 750469AA6 19,342 21,000,000 PRN DFND 01 21,000,000 0 0
REATA PHARMACEUTICALS INC CL A 75615P103 21,316 609,554 SH DFND 01 609,554 0 0
REGENXBIO INC COM 75901B107 8,969 125,000 SH DFND 01 125,000 0 0
RHYTHM PHARMACEUTICALS INC COM 76243J105 21,995 703,600 SH DFND 01 703,600 0 0
ROCKET PHARMACEUTICALS INC COM 77313F106 5,496 280,000 SH DFND 01 280,000 0 0
SAREPTA THERAPEUTICS INC COM 803607100 39,125 296,000 SH DFND 01 296,000 0 0
SELECT MED HLDGS CORP COM 81619Q105 33,723 1,858,000 SH DFND 01 1,858,000 0 0
SIENTRA INC COM 82621J105 12,664 649,100 SH DFND 01 649,100 0 0
SIERRA ONCOLOGY INC COM 82640U107 5,224 1,764,889 SH DFND 01 1,764,889 0 0
SOLID BIOSCIENCES INC COM 83422E105 6,391 179,381 SH DFND 01 179,381 0 0
STEADYMED LTD SHS M84920103 4,132 918,120 SH DFND 01 918,120 0 0
SYNLOGIC INC COM 87166L100 13,419 1,365,143 SH DFND 01 1,365,143 0 0
SYROS PHARMACEUTICALS INC COM 87184Q107 12,956 1,268,945 SH DFND 01 1,268,945 0 0
TANDEM DIABETES CARE INC COM NEW 875372203 56,664 2,573,305 SH DFND 01 2,573,305 0 0
TELIGENT INC NEW COM 87960W104 2,453 708,873 SH DFND 01 708,873 0 0
TELIGENT INC NEW NOTE 4.750% 5/0 87960WAA2 10,312 9,567,000 PRN DFND 01 9,567,000 0 0
TRANSLATE BIO INC COM 89374L104 8,223 650,000 SH DFND 01 650,000 0 0
TRINITY BIOTECH INVT LTD NOTE 4.000% 4/0 89643QAB4 35,398 43,000,000 PRN DFND 01 43,000,000 0 0
UNIVERSAL HLTH SVCS INC CL B 913903100 29,197 262,000 SH DFND 01 262,000 0 0
VOYAGER THERAPEUTICS INC COM 92915B106 2,299 117,647 SH DFND 01 117,647 0 0
WALGREENS BOOTS ALLIANCE INC COM 931427108 31,868 531,000 SH DFND 01 531,000 0 0
WAVE LIFE SCIENCES LTD SHS Y95308105 6,839 178,806 SH DFND 01 178,806 0 0
WRIGHT MED GROUP N V ORD SHS 0.03 PAR N96617118 9,074 349,539 SH DFND 01 349,539 0 0
WRIGHT MED GROUP N V NOTE 2.250%11/1 98236JAB4 41,943 31,500,000 PRN DFND 01 31,500,000 0 0
XENCOR INC COM 98401F105 1,790 48,366 SH DFND 01 48,366 0 0
XERIS PHARMACEUTICALS INC COM 98422L107 47,425 2,498,666 SH DFND 01 2,498,666 0 0
ZIMMER BIOMET HLDGS INC COM 98956P102 13,484 121,000 SH DFND 01 121,000 0 0