Findings on the psychomotor activity of unipolar versus bipolar depressive patients and on the relationship between psychomotor activity and sleep are divergent. In this study, the psychomotor activity of 37 depressive patients (25 unipolar, 12 bipolar) was examined by means of continuous actometric monitoring (48 h). The mean activity level of the unipolar depressives is higher (though not at a significant level) than that of the bipolar group. There is a weak but significant negative correlation between psychomotor activity and self-rated sleep time. Elderly and female patients display greater psychomotor activity than younger depressives and male patients. After matching for age and gender, the psychomotor activity of unipolar and bipolar patients is virtually identical; a significant correlation between psychomotor activity and sleep time cannot be established any more.