The aim of this study was to describe the clinical characteristics and the polysomnographic findings of a sample of patients affected by sleep-related painful erections (SRPE). In a 6-y period 18 patients were diagnosed as having SRPE. The mean age at the onset of the disease was 39.8 +/- 11.6 y and the mean duration of SRPE was 5.4 +/- 3.5 y. According to ICSD criteria, about 60% of patients had a severe form of the disease. None of the patients met any DSM IV Axis-I and Axis-II diagnoses. Twelve patients complained of excessive daytime sleepiness. SRPE patients, compared to age-matched controls, showed a reduced sleep efficiency, an increased wake after sleep onset and a reduced percentage of REM sleep. This study confirms that in SRPE there are no clear predisposing factors, no familial pattern, but REM sleep fragmentation. Concerning the pharmacological treatment, in the history of patients, propranolol and paroxetine, but not amitriptiline and lorazepam, showed a temporary efficacy in some patients.