From January 1986 to December 1991, 6 cases of acquired phimosis secondary to balanitis xerotica obliterans were observed. The authors report their experience in the diagnosis and treatment of this disease. Five patients were treated with plastic of the foreskin, one was circumcised and treated with local instillation of corticoids. The authors conclude that the histological study of the specimen is very important to demonstrate the nature of the lesion