Eighteen patients with plastic induration of the penis were treated with procarbazine, a cytotoxic agent. Ten patients experienced a good to excellent result; 7 patients no improvement and in one patient treatment had to be prematurely withdrawn because of gastro-intestinal side-effects. No other serious side-effects occurred in the present investigation. Patients with impaired erection, previous gastric surgery and alcoholics are deemed less suitable for this form of therapy. It can be recommended to other patients in otherwise good condition and is especially suitable when diffuse fibrosis is present or when cavernosography indicates deep infiltration of the disease into the intercavernous septum. Selection can be made from those patients who show no tendency to spontaneous remission or those unsuitable for or unresponsive to other therapeutic measures.