A case-control study was performed in order to assess risk factors for repeated sexually transmitted diseases. The study comprised 101 patients who had had sexually transmitted diseases 3 or more times during their lives and 182 controls who had no history of sexually transmitted disease. The subjects all attended the City Department for Skin and Venereal Diseases in Belgrade, Yugoslavia, from June 1997 to April 1998. According to multivariate logistic regression analysis, sexually transmitted diseases repeaters, in comparison with the controls, were older, more frequently divorced and widowed and without a regular partner, had more sexual partners and more sexual intercourse, and had more frequent sexual contact with people on the same day as meeting them. They also consumed alcohol, used sedatives and were prosecuted for criminal offences more frequently than the controls. The results of this study support the hypothesis that sexually transmitted diseases repeaters are different from their controls in terms of their behavioural and social characteristics.