| Name | Deductibility Code |
| 343 House Inc. | 4 |
| Church of the Open Door Ministries Incorporated | -- |
| Custer Institute Inc. | -- |
| East End Disabled Benevolent Fund Incorporated | -- |
| Faith Gospel Missionary Outreach | -- |
| Faith Reformed Baptist Church Inc. | -- |
| First Universalist Church of Southold | -- |
| Friends of the Southold Free Library | -- |
| Full Sea Inc. | -- |
| Group for the East End Inc. | -- |
| Incorporated Long Island Chpt of the N Y State Archaeological Assoc | -- |
| International Plant Propagators Society Inc. Eastern Region Fdn | -- |
| Joseph and Katherine Macari Foundation Inc. | 4 |
| Lost at Sea Memorial Fund | -- |
| May Foundation Trust | 4 |
| North Fork Animal Welfare League Inc. | -- |
| Peconic Gardiners Junior Sailing Association Inc. | -- |
| Save the Peconic Bays Inc. | -- |
| Sea Tow Boating Safety & Education Foundation Inc. | -- |
| Southold Free Library | -- |
| Southold Historical Society Inc. | -- |
| Southold Raynor Animal Shelter Foundation Inc. | -- |
| Southold School Athletic Association | -- |
| Southold Sunshine Society Inc. | -- |
| Southold Voice Inc. | -- |
| Suffolk Vietnam Veterans Memorial Commission Inc. | -- |
| Summer Showcase Concert Series of Southold Inc. | -- |
| The Guidance Center Services Inc. | -- |