Objectives: To evaluate the cross-sectional association between lower urinary tract symptoms (LUTS) severity and sexual function in a population-based sample of men and the extent to which this association might be explained by age. Subjects and Methods: Subjects in The Olmsted County Study of Urinary Symptoms and Health Status Among Men (55% participation rate) included 2115 white men aged 40 to 79 years; subjects were recruited on January 1, 1990, from a random sample identified through the Rochester Epidemiology Project. At baseline in 1990 and biennially thereafter, these men completed a self-administered questionnaire that assessed LUTS severity with questions similar to those of the American Urological Association Symptom Index. At the 6-year follow-up, 11 previously validated questions about male sexual function from the Brief Sexual Function Inventory were added. Results: Overall, each of the sexual function domains (sexual drive, erectile function, ejaculatory function, problem assessment, and overall sexual satisfaction) was inversely associated with the severity of LUTS, with Spearman correlation coefficients ranging from -0.21 to -0.31 (all P<.001). In age-adjusted analyses, the ejaculatory function and problem assessment domains were most strongly associated with overall LUTS severity, whereas the association with sexual drive was substantially diminished. Little difference was noted in the magnitude of association between sexual function and either obstructive or irritative symptoms. Conclusions: The cross-sectional data suggest that sexual function is inversely associated with LUTS severity and that this association is only partially attributable to the confounding effects of age.