- Clarence Lilien and Associates2
- Clarence Lilien and Sons1
- Clarence R. Knickman, inc.1
- Claridge Realty Corp.1
- Clark T. Chambers, Inc.1
- Clark, Fred G. (Fred George), 1890-19731
- Clark-Robinson Corp.1
- Clawson, Harry M.3
- Clayton Apartments, Inc.1
- Clifton Manor Apartments, Inc.1
- Clinton Construction Corp.1
- Clinton Terraces, Inc.1
- Clinton and Russell1
- Clover Building Corp.1
- Cloverton Corp.1
- Clyde Management Corp.6
- Cohen Brothers Realty6
- Cohen Brothers Realty and Construction Corp.7
- Cohen and Lowenfish2
- Cohen and Siegel1
- Cohen, Jacob2
- Cohen, Rabbi Eugene1
- Cohen, Samuel3
- Cohn Brothers55
- Colasono and Petrides1
- Coldwell Banker1
- Cole Brothers2
- Colemont Realty Corp.1
- Collins, Tuttle and Co.9
- Colonial Apartments, Inc.1
- Colonial Realty Co., Inc.1
- Colony Estates, Inc.2
- Colony Gardens, Inc.1
- Colton Realty Corp.1
- Columbia University1
- Columbia University College of Physicians and Surgeons1
- Columbia University. Department of Music1
- Columbia University. Faculty of Political Science1
- Columbia University. Press1
- Columbia-Clark Corp.1
- Commercial Builders, Inc.1
- Commission on Interracial Cooperation1
- Commodore Construction Co., Inc.1
- Community Development Agency1
- Concourse Development, Inc.1
- Conforti, James, Jr.2
- Congregation Netsah Israel, Inc.1
- Congress Gardens, Inc.1
- Connelly Brothers1
- Construction and Development Corp. of New York1
- Convertible Homes, Inc.1
- Cooper-Bregstein Realty Co.9
- Cooperman, Philip1
- Corbin Terrace Apartments, Inc.1
- Corcoran, Francis L.1
- Corcorar, Francis2
- Cord Meyer Co.1
- Cord-Meyer Development Co.4
- Corey, Russel B.1
- Cornay Realty Corp.2