This was a primary health care (PHC) study aiming at the investigation of the prevalence and nature of sexual dysfunction among a sample of type II diabetic men, in comparison with the control groups of hypertensive men and apparently healthy men with no chronic medical illness. Subjects were assessed by PHC physicians using a sexual dysfunction semistructured questionnaire and a questionnaire designed for medical history and sociodemographic data. Clinical assessments for peripheral vascular disease and peripheral neuropathy were carried out for the diabetic group only. The estimated high prevalence rate of sexual dysfunction among the diabetic group (89.2%) was significantly greater than the hypertensive group (43.6%), and the apparently healthy group (16.7%). The commonest clinical presentations of sexual dysfunction among the diabetic men were impaired morning and spontaneous erections. erectile weakness, and ejaculatory disturbances. Lesser common presentations were reduced sexual interest and complete erectile failure. Then were no significant associations between the sexual dysfunction and clinically obvious physical complications of diabetes, or factors that might affect sexual functioning (i.e., alcohol or drug misuse or marital disharmony). However, the validity of these results is questioned due to the small numbers used for statistical analysis. (C) 1997 Elsevier Science Inc.