Reliable empiric estimates of the prevalence and career longevity of prostitute women in the United States are not currently available. We analyze data from our continuous observation of such women in Colorado Springs, during nearly two decades, starting in 1970. Of the 1,022 prostitute women observed, 52.5% are classified as evanescent, 12.1% as short‐term, and 35.3% as long‐term residents. Comparison with police prostitution records suggests that our cohort represents about four‐fifths of“true”prevalence. The density of full‐time equivalent prostitutes (FTEPs) appears to be about 23 per 100,000 population. By extension to the nation, we estimate that an average of about 84,000 women, or about 59,000 FTEPs, worked as prostitutes in the United States annually during the 1980s. Our data suggest that prostitute women remain in prostitution for only a short time (about 4 or 5 years for long‐term prostitutes).