The relation between age, sleep disorders, nocturnal penile tumescence, and sexual behavior was investigated in 70 healthy married men aged 45-75 years. They had an extensive psychosexual interview, a medical and psychiatric evaluation, and were studied in the sleep laboratory for four nights. Electroencephalogram (EEG), eye movements, muscle tone, and penile tumescence were monitored continuously, and respiratory airflow and bilateral anterior tibialis recordings were obtained during the first sleep session. There was a marked age-related increase in sleep-disordered breathing, but no significant changes in periodic leg movements with age. Respiratory distress and periodic leg movement (PLM) indices were mostly unrelated with nocturnal penile tumescence (NPT) measures as well as with all sexual behavior dimensions when age was taken into account in the analysis of results. Men with a respiratory distress disorder did not differ from a nondisordered group of similar age in NPT and behavioral parameters. Men with PLM disorder differed from their comparison group in only two variables: fewer number of maximum tumescent episodes and less frequent sexual thoughts. Men who met criteria for erectile impotence did not differ significantly in degree of respiratory or PLM disturbances or in the prevalence of sleep disorders when compared to an aged-matched sexually nondysfunctional group. The overall results did not support the notion that sleep disorders are involved in the increased prevalence of erectile impotence in healthy older individuals. Assessment of blood oxygenation and respiratory effort, in addition to airflow, need to be carried out before final conclusions can be drawn on the significance of sleep-disordered breathing in male sexuality.