To evaluate the incidence of erectile dysfunction (ED) in men with unrelated urologic conditions paying special attention to the reasons for patient under-reporting. We asked 500 consecutive men over age 50 visiting their urologist's office for problems unrelated to ED, whether or not they had any difficulty with their potency. Those who gave a positive response were then asked to complete a questionnaire to assess their reasons for under-reporting and whether they had had any previous discussions with their primary-care physicians regarding their sexual function. Out of 500 men, 218 (44%) reported experiencing some degree of ED. Reasons for failure to discuss ED with their urologist included: 161 out of 218 (74%) were embarrassed; 27 out of 218 (12%) felt that ED was a natural part of aging; 20 out of 218 (9%) were unaware that urologists dealt with the problem of ED; and 10 out of 218 (5%) did not consider the problem worthy of attention. Only 48 of the 218 men with ED reported having previous discussions about their problem with their primary-care physicians. Of the 170 patients who did not report having such discussions, 140 (82%) reported that they would have liked their primary-care physician to have initiated a discussion of ED during their routine visits. In conclusion. a significant percentage of older men with some unrelated urologic complaint also suffer from some degree of ED and remain undiagnosed unless specifically questioned about this problem. By far, the most common reason for under-reporting of ED was patient embarrassment. While urologists are able to elicit information regarding erectile function on specific questioning, patients appear comfortable and willing to discuss their potency with primary-care physicians.