65 patients with penetrating or blunt scrotal trauma underwent scrotal ultrasound. High-resolution real-time sonography was able to differentiate testicular from extratesticular lesions in all cases. Lesions of the epididymis were diagnosed in 14 cases. In epididymal haematoma sonography revealed an hyperechoic enlarged epididymis whereas posttraumatic epididymitis was demonstrable as hypoechoic swelling. 14 testicular ruptures and 6 testicular haematomas without disruption of the tunica albuginea were correctly diagnosed. Diagnosis could be confirmed at operation in 12 cases and by clinical and sonographic follow-up in 8 cases. A heterogeneous parenchymal pattern, contour abnormalities, poorly defined margins and obvious fragmentation of the testicle strongly suggest testicular rupture.