This is a report of an open clinical trial of Carbamazepine in the treatment of patients who suffered from affective disorders and who did not have an adequate response to Lithium or other medications. Our findings suggest that Carbamazepine can be a useful adjunctive medication when used in combination with Lithium and other psychotropic medications. The characteristics of the patients who responded were examined. The clinical state of the patients at the point of intervention varied; eight patients were manic and four patients were depressed. Four patients were judged to have had markedly effective responses, four showed an effective response and in four there was a slightly effective response. From the duration of the trials it was evident that in cases where Carbamazepine produced a good response its effect was seen as early as two weeks. The mean daily dose used varied from 300-1300 mgs. Because of the open nature of this trial, Carbamazepine was not withdrawn except in one instance.