Between 1973 and 1991, 13 patients with malakoplakia (MKP) have been diagnosed and treated. The lesions involved all sites in the genitourinary tract; 2 patients had multiple and 11 had single lesions. Treatment was based on 2 criteria: (a) pharmacological treatment with trimethoprim-sulphamethoxazole and/or ascorbic acid and/or bethanechol chloride; (b) excision of the MKP lesion either endoscopically or by open surgery. Two patients died (1 from multiple MKP and the other from a myocardial infarct); the remainder did well. The pathogenic, diagnostic and therapeutic aspects of the disease are discussed.