Brofaromine is a selective and reversible inhibitor of monoamine oxidase A. The efficacy and safety of this compound as compared with tricyclic antidepressants, classical monoamine oxidase inhibitors and placebo has been demonstrated in several clinical trials. The present 6-week, double-blind, randomized trial compared brofaromine with imipramine in in-patients with major depression. Brofaromine was as effective as imipramine in the treatment of major depression, but exhibited a different side-effect profile, in particular lacking the anticholinergic and certain cardiovascular side-effects of the tricyclic imipramine, but more likely to induce sleep disturbances. In this study, in-patients were examined, since the majority of controlled clinical trials on depressed patients conducted so far have focused on the evaluation of out-patients. If one assumes that a different degree of severity of depression exists between these two patient groups, then the results of those trials conducted on out-patients cannot readily be transferred to in-patients.