The objective was to investigate how prostate cancer and its treatment affects sexual, urinary and bowel functions and to what extent eventual complications cause distress. A questionnaire was sent to 431 men aged 50-80 years with prostate cancer diagnosed in 1992 in the Stockholm area (Sweden) and 435 randomly selected men with a similar age distribution. Sexual function, as compared with their youth, was diminished in a majority of all men. The prostate cancer patients were, however, more likely to report low frequency and/or intensity in all aspects of sexual function. A majority of the men were distressed by a waning sexual capacity. The proportion of men with prostate cancer who were severely distressed owing to a decline in sexual function was larger than in the reference group. The willingness to trade off an intact sexual function for long-term survival varied considerably among the men in the reference group. Urinary and bowel symptoms were less common than a waning sexual function in both groups, and few appeared to be severely distressed by urinary or bowel symptoms. A decline in sexual functions was the most common cause of disease-specific distress in men with prostate cancer.