The injury to the scrotum occurs infrequently due to its mobility and position. If rupture of testis or epididymis following scrotal trauma has developed, early and accurate diagnosis is mandatory to salvage the testis or epididymis. We have used scrotal ultrasound as a diagnostic tool for prompt and correct diagnosis of scrotal trauma. Of the 34 cases of scrotal trauma, scrtal ultrasonography was taken in 26 cases. Homogenous echoes of testis without disrupted its margin surrounded by dense cluster of echoes was the finding seen in the scrotal hematoma (n=11) whereas ill-defined testicular or epididymal margin with heterogenous intratesticular echogenicity or extratesticular protrusion of heterogenous mass were shown in the testicular or epididymal rupture(n=15) by scrotal ultrasonogram. We explored scrotum in 18 cases which were suspected as testicular rupture, epididymal rupture or large intrascrotal hematoma and compared the operative finding to the preoperative views of scrotal ultrasound. All case except one showed the same finding with the preoperative scrotal ultrasound but one case diagnosed as testicular rupture by scrotal ultrasound showed only a huge simple scrotal hematoma without testicular rupture. We found that scrotal ultrasound is very helpful for early, accurate diagnosis of scrotal trauma and the decision of adequate treatment.