The authors’ goal was to test the hypothesis that the antidepressant effect of total sleep deprivation can be maintained by initially avoiding sleep during a supposedly “critical” time period in the early morning. They studied 33 inpatients with major depression, melancholic type, all of whom responded positively to total sleep deprivation. Twelve of the patients were men and 21 were women; their mean age was 46.7 years (SD= 13.7). After total sleep deprivation, the patients started a sleep schedule from 5: 00 pm to 12: 00 midnight, which then was shifted back by 1 hour each day until a sleep time of 11: 00 pm to 6: 00 am was reached. Twenty (61%) of the 33 patients who responded to total sleep deprivation with an improved state of mood maintained this improvement during sleep phase advance therapy. Drug-free and medicated patients did not differ from each other. The rapid amelioration of mood observed with total sleep deprivation can be preserved with a succeeding phase shift of the sleep period.