Abstract Objectives: Due to demographic developments in industrial nations, age-correlated diseases are becoming more important. From many epidemiological studies we know that the prevalence of benign prostatic hyperplasia (BPH) and the loss of erectile function (= erectile dysfunction or ED) increase with advancing age. Are these two illnesses related or/and independent? Methods: We mailed our newly developed and validated questionnaire on male erectile dysfunction (KEED), as well as a set of questions pertaining to voiding problems (IPSS), to a representative population sample of 8000 men from 30 to 80 years of age residing in the city of Cologne. Results: The responses included 4489 evaluable replies (56.1%). The response rates in the different age groups ranged from 41 to 61%. The mean age of the men who answered was 51.8 years. The overall prevalence of ED was 19.2% ( n=862), with a steep age-related increase from 2 to 53%. Furthermore, 31.2% ( n=1957) of all men complained of lower urinary tract symptoms (LUTS), the prevalence and the intensity of which increased with age. Interestingly, a high co-morbidity was found between ED and voiding problems. Prevalence of LUTS in men suffering from ED was about 72.2% ( n=621) vs. 37.7% (1367) in men with normal erections. The odds ratio was evaluated with 2.11. The trivariate analysis showed that the occurrence of LUTS can be considered as an age-independent risk factor for the development of ED ( p<0.001). Conclusions: Even though the pathogenetic relationship between LUTS and ED is not yet completely understood, one has to postulate a direct association between these two typical symptom complexes in the aging male.