Patients referring to the Urology and/or Endocrinology Departments of Ankara Medical School with complaints of diabetes mellitus (DM) and related complications were evaluated during the last year. A detailed history was obtained and all of the patients were questioned especially about sexual function problems. Following this evaluation, all patients were divided into two main groups, i.e. patients with sexual disorders, and those with normal sexual function. Factors such as BPH, cerebrosclerosis and other important vascular-neurologic pathologies which may play a role in the etiology of impotence were excluded from the study and 38 patients with sexual dysfunction and 15 with normal sexual activities have undergone further evaluation. Following routine blood and urine analyses, serum hormone levels (testosterone, FSH, LH, prolactin) were determined. Penile color-flow doppler analysis, cavernosometry, cavernosography, bulbocavernous reflex latency time and evaluation of somatosensory evoked potentials were performed. Additionally, all patients were evaluated from the psychiatric aspect using the Hamilton depression scale and MMPI questionnaire. The presence of vascular or neurologic pathology in 89.4% of our patients and of both pathologies in 39.4% of the patients, indicated the importance of multifactorial evaluation of diabetic impotence in order to plan a complete and efficient therapy program.