In a double-blind study we compared fluvoxamine, a new selective serotonin re-uptake inhibitor, with clomipramine. In 36 female inpatients with vital depression, the antidepressant properties of fluvoxamine and clomipramine were studied. Eight patients did not complete the study. During a 4-week treatment period the Hamilton-, Zung-, Clinical Global Impression- and Leyden ratings showed, apart from the last scale in the fluvoxamine group, significant improvement in both groups. In the latter scale, a statistically significant difference was found in favour of clomipramine. Additional anxiolytic-sedative medication was required equally in both groups. CSF data in 10 patients are discussed. Non-specific electrocardiographic (ECG) repolarization disturbances were observed in both groups. Anticholinergic side effects were more prominent with clomipramine than with fluvoxamine; gastrointestinal symptoms and agitation were more prominent with fluvoxamine than with clomipramine. Fluvoxamine did not show particular advantages or disadvantages over clomipramine.