Syphilis among active duty soldiers at Fort Bragg, North Carolina, and the nonmilitary population of Cumberland County was examined during a 9-year period encompassing the most recent nationwide syphilis epidemic. A total of 762 cases of primary and secondary syphilis were recorded between 1985 and 1993, 27% of which occurred in soldiers. The epidemic struck both military and civilian populations simultaneously; epidemic curves in the two populations were parallel, peaking in 1990-1991, with highest annual incidences of 122.6/ 100,000 (military) and 48.0/100,000 (civilian). Individual risk factor data were not available for analysis, but a relationship was observed between primary and secondary syphilis diagnoses in both populations and cocaine arrests in Cumberland County. Our findings provide epidemiological support for a high degree of interplay between the military and the surrounding civilian communities that has significant implications for control of sexually transmitted diseases. Enhanced collaboration between military and civilian public health authorities is essential to the control of syphilis and other sexually transmitted diseases.