Twenty-four hour urinary excretion of 3-methoxy-4-hydroxyphenyl-glycol (MHPG) was analyzed in 48 unipolar and 19 bipolar depressed patients and 16 healthy controls. All patients were interviewed using the Schedule for Affective Disorders and Schizophrenia. Various symptoms and descriptive variables were correlated univariately with urinary MHPG in two random groups, and those items showing a trend in both splits were further reduced by a multiple regression technique, first on each split separately and finally on the pooled sample. Urinary MHPG correlated significantly both in uni- and multivariate tests with age (positively, but only in females), altered motor activity (summed scores of agitation and retardation during the worst week of present or recent depression), and with existence of at least one suicide attempt before the present depressive episode (last items negatively). There were no differences between unipolar and bipolar patients, or between any patient group and the healthy controls. Males excreted about 25% more MHPG than females. Levels of MHPG in urine and cerebrospinal fluid were highly significantly intercorrelated.