Serology tests were made on 1,985 blood specimens drawn between September 1963 and February 1967. Seven hundred and eighteen cases of late syphilis were identified with the fluorescent treponemal antibody absorption (FTAABS) test. Only 441 (61%) patients had a reactive venereal disease research laboratory test for syphilis (VDRL). A sizeable percentage of late syphilitic cases (39%) seen in this study may have been overlooked if only a reagin test had been used to exclude or confirm the diagnosis.