Nineteen physicians participating in a program for detecting and treating gonorrhea and other sexually transmitted diseases (STD) in high-risk groups filled out encounter forms for the initial visits by the first 3144 patients. This information was used to describe the program users and, by means of logistic regression analysis, to identify predictors of gonorrhea in asymptomatic patients. Overall, 17.3% of the users had culture-proved gonorrhea. Of the symptomatic patients 24.5% had gonorrhea. Of the asymptomatic patients 20.4% of those with a history of contact with a known or suspected case of STD had the disease, and 5.3% of those without a history of contact had the disease. The independent predictors of gonorrhea identified were, in order of importance, a history of contact with a case of STD and being aged less than 30 years. These predictors underline the importance of contact tracing, an underused but productive method of gonorrhea control that can be used effectively in private practice.