| Community Transportation NetworkEIN 35-2109955 | Human Services | IN | $1,291,221Small | 94.81 |
| Community Voices Heard (CVH)EIN 13-3901997 | Community Development | NY | $1,562,711Small | 94.72 |
| Community Volunteers in Medicine EIN 23-2944553 | Health | PA | $7,788,662Mid-sized | 100.00 |
| Community WorksEIN 93-0633804 | Human Services | OR | $1,713,787Small | 75.05 |
| COMPASEIN 41-1228092 | Arts, Culture, Humanities | MN | $1,375,763Small | 85.95 |
| Compassion & ChoicesEIN 84-1328829 | Human and Civil Rights | CO | $14,808,739Large | 96.56 |
| Compassion InternationalEIN 36-2423707 | International | CO | $861,733,317Large | 84.76 |
| Compassion Over KillingEIN 52-2034417 | Animals | DC | $1,632,731Small | 78.78 |
| Compassionate Care ALSEIN 04-3567819 | Health | MA | $1,330,284Small | 93.12 |
| CompassPoint Nonprofit ServicesEIN 93-1196632 | Community Development | CA | $3,901,504Mid-sized | 90.56 |
| Concern AmericaEIN 23-7273488 | International | CA | $1,061,339Small | 72.84 |
| Concern FoundationEIN 23-7002878 | Health | CA | $1,792,550Small | 84.42 |
| Concern Worldwide US, Inc.EIN 13-3712030 | International | NY | $42,569,967Large | 90.91 |
| Concerned Women for AmericaEIN 95-3580834 | Human and Civil Rights | DC | $3,799,892Mid-sized | 77.44 |
| Concerns of Police SurvivorsEIN 52-1354370 | Human Services | MO | $4,382,937Mid-sized | 92.22 |
| Concert Artists GuildEIN 13-1854253 | Arts, Culture, Humanities | NY | $1,562,144Small | 80.14 |
| Concord MuseumEIN 04-2104035 | Arts, Culture, Humanities | MA | $2,742,553Small | 81.67 |
| Conexión AméricasEIN 62-1715618 | Human Services | TN | $2,437,718Small | 91.45 |
| Conference of Presidents of Major American Jewish Organizations FundEIN 13-3116652 | International | NY | $1,975,532Small | 77.02 |
| Congressional Black Caucus FoundationEIN 52-1160561 | Research and Public Policy | DC | $7,300,039Mid-sized | 89.01 |
| Congressional Medal of Honor FoundationEIN 25-1828488 | Human and Civil Rights | VA | $4,580,569Mid-sized | 100.00 |
| Congressional Sportsmen's FoundationEIN 52-1686163 | Animals | DC | $4,450,193Mid-sized | 78.44 |
| ConnCANEIN 20-1612161 | Education | CT | $2,013,054Small | 76.38 |
| Connect2Help 2-1-1EIN 31-1216792 | Human Services | IN | $2,490,328Small | 88.76 |
| Connecticut Association for Human ServicesEIN 06-0653158 | Research and Public Policy | CT | $1,624,056Small | 86.93 |
| Connecticut Audubon SocietyEIN 06-0653531 | Environment | CT | $3,731,785Mid-sized | 94.19 |
| Connecticut Cancer FoundationEIN 06-1240574 | Health | CT | $942,787Small | 88.74 |
| Connecticut Food BankEIN 06-1063025 | Human Services | CT | $48,839,774Large | 91.03 |
| Connecticut Fund for the EnvironmentEIN 06-0990195 | Environment | CT | $3,663,406Mid-sized | 92.37 |
| Connecticut Historical SocietyEIN 06-6026012 | Arts, Culture, Humanities | CT | $3,041,718Small | 85.24 |
| Connecticut Humane SocietyEIN 06-0667605 | Animals | CT | $8,990,903Mid-sized | 89.17 |
| Connecticut LandmarksEIN 06-0789151 | Arts, Culture, Humanities | CT | $1,955,963Small | 90.31 |
| Connecticut Legal ServicesEIN 06-0955461 | Human and Civil Rights | CT | $11,944,323Mid-sized | 79.00 |
| Connecticut Public BroadcastingEIN 06-0758938 | Arts, Culture, Humanities | CT | $22,123,694Large | 85.22 |
| Connecticut Voices for ChildrenEIN 06-1435280 | Human Services | CT | $1,151,496Small | 90.86 |
| Connections for Abused Women and their ChildrenEIN 36-2950380 | Human Services | IL | $1,833,855Small | 94.58 |
| Connie Maxwell Children's HomeEIN 57-0324927 | Human Services | SC | $9,553,199Mid-sized | 87.85 |
| Conquer Cancer Foundation of the American Society of Clinical OncologyEIN 31-1667995 | Health | VA | $27,245,874Large | 95.85 |
| Conservancy for Cuyahoga Valley National ParkEIN 34-1917257 | Environment | OH | $4,242,928Mid-sized | 88.91 |
| Conservancy of Southwest FloridaEIN 59-1157084 | Environment | FL | $8,102,079Mid-sized | 93.89 |
| Conservation Colorado Education FundEIN 84-0614285 | Environment | CO | $1,902,201Small | 92.20 |
| Conservation Foundation of the Gulf CoastEIN 20-0345249 | Environment | FL | $1,097,099Small | 95.85 |
| Conservation InternationalEIN 52-1497470 | Environment | VA | $149,806,220Large | 95.88 |
| Conservation Lands FoundationEIN 20-8924520 | Environment | CO | $7,028,672Mid-sized | 94.33 |
| Conservation Law FoundationEIN 04-6149986 | Environment | MA | $9,439,409Mid-sized | 91.21 |
| Conservation MinnesotaEIN 41-2017329 | Environment | MN | $1,455,520Small | 88.06 |
| Conservation NorthwestEIN 94-3091547 | Environment | WA | $2,055,902Small | 87.29 |
| Conservation Strategy FundEIN 94-3294843 | Environment | DC | $2,079,533Small | 87.92 |
| Consortium for Graduate Study in ManagementEIN 43-0962198 | Education | MO | $36,743,080Large | 84.82 |
| Constitutional Accountability CenterEIN 52-2063854 | Research and Public Policy | DC | $3,469,685Small | 91.86 |
| Constitutional Rights FoundationEIN 95-2219680 | Education | CA | $1,944,718Small | 86.71 |
| Contemplative OutreachEIN 13-3345685 | Religion | NJ | $864,788Small | 80.86 |
| Contemporary Art Museum St. LouisEIN 43-1202816 | Arts, Culture, Humanities | MO | $2,732,507Small | 91.49 |
| Contemporary Arts Center, CincinnatiEIN 31-0590095 | Arts, Culture, Humanities | OH | $4,498,292Mid-sized | 84.87 |
| Contemporary Arts Center, New OrleansEIN 72-0798830 | Arts, Culture, Humanities | LA | $3,623,733Mid-sized | 87.95 |
| Contemporary Arts Museum HoustonEIN 74-1093771 | Arts, Culture, Humanities | TX | $2,751,030Small | 83.77 |
| Contemporary Jewish MuseumEIN 47-0920831 | Arts, Culture, Humanities | CA | $10,845,438Mid-sized | 76.22 |
| Continental Baptist MissionsEIN 38-1398829 | Religion | MI | $2,527,365Small | 74.84 |
| Convalescent Aid SocietyEIN 95-1782304 | Health | CA | $1,081,202Small | 88.51 |
| Convoy of HopeEIN 68-0051386 | Human Services | MO | $157,932,066Large | 96.46 |