Smooth tissue sarcomas represent less than 1% of adult malignant tumours and 10 to 20% of teenagers and young adult tumours [1-4]. Genito-urinary forms are extremely rare and represent 1% to 2% of malignant tumours of the urogenita sphere [4]. There are several subtypes of smooth tissue sarcomas, and the most aggressive histological types are the liposarcoma, the leiomyosarcoma and the undifferentiated pleomorphic sarcoma [5]. Such histopathological diversity constitutes one of the anatomopathological diagnosis difficulties, essentially based on morphological, immunohistochemical and genetical analyzes [5]. The clinical signs are non-specific and most often reflect a banal stricture of urethra, which delays diagnosis. We present the first case of unclassifiable undifferentiated male urethra sarcoma, unusual by its localization and circumstances of discovery.