The authors explored the relationship between the antiobsessional and antidepressant effects of tricyclic drugs in primary obsessive-compulsive disorders. Study 1 consisted of a controlled 12-week trial with clomipramine (N = 7) and placebo (N = 5); study 2 analyzed the pooled data from 15 patients uniformly selected and treated with either clomipramine or imipramine. Although the antiobsessional and antidepressant effects of the drugs covaried, their antidepressant action was not a prerequisite for their antiobsessional effect. The findings suggest that clomipramine and probably imipramine possess specific antiobsessive effects that are at least partially independent of their antidepressant effects.