In this paper, three placebo-controlled trials of moclobemide, and four three-way comparison trials of moclobemide, placebo and one of the standard tricyclic antidepressants, imipramine, clomipramine, or amitriptyline, are reviewed. The results of the placebo-controlled trials indicate that about twice as many of the patients receiving moclobemide showed a marked improvement during a four-week treatment period, as compared with patients receiving placebo. Of the three-way trials, two studies indicated that the efficacy of moclobemide was significantly greater than that of placebo and similar to that of other antidepressants (imipramine or amitriptyline). Tolerance of moclobemide was good and better than that of the tricyclic antidepressants. In the other three-way comparison trials, the differences in efficacy between the placebo, moclobemide, and the tricyclic antidepressant were not significant.