Disturbed sleep is characteristic of patients with mood disorders and most patients with major depression complain of insomnia. In schizophrenia a slow wave sleep (SWS) deficit has been suggested to be the prevailing alternation in the electroencephalographic (EEG) sleep pattern. This study conducted with the aim of detecting possible significant differences in sleep pattern between patients suffering from schizophrenia and depressive disorder. This study was a case control comparative study conducted on 60 patients, selected from department of psychiatry Kasr EL-Aini and emergency room of institute of psychiatry Ain shams University. In addition, this study included 30 healthy individuals who matched patient group for age and sex. There was a statistically significant difference on all sleep parameters between patients and control group. Findings indicate quantitative rather than qualitative difference between the two patient group. This draws the attention to the possibility that both disorders may be on the same continuum of pathology rather than arising from different pathologies, an idea held for long.