Isocarboxazide has been used as long‐term treatment for a selected group of 20 depressive patients, of whom some 90% (17/19) were non‐responders to treatment with tricyclic antidepressants. At the follow‐up the median duration of illness was 162 months, and the median duration of treatment was 42 months. Side‐effects and interactions were moderate thus legitimating a treatment procedure on which all the patients of the material responded better than on any other antidepressive treatment.Treatment with monoamine‐oxidase‐inhibitors, like isocarboxazide, should not be left untried in the case of therapy‐resistant depression.