Sleep polygraphic recordings were performed in six unmedicated male manics, in age and sex matched unipolar and bipolar depressives and in normal controls. No difference was evidenced between manics, depressives and controls when percentages of sleep stages 1, 2, 3, 4 and REM were considered. Manics demonstrated poorer sleep efficiency, longer sleep onset latency and reduced sleep period time than normal controls but no more so than in our depressed patients. None of the classical sleep disturbances reported in depression (short REM latency, decreased delta sleep and increased REM density) were observed in mania suggesting that with the exception of sleep continuity disturbances, sleep in mania is comparable to sleep in normal subjects.