Color Doppler ultrasonography was performed in 41 patients with the acute onset of scrotal pain. of the 32 cases of 33 inflammatory diseases( epididymitis n=19, epididymo-orchitis n=12, orchitis n=1) color Doppler image demonstrated increased epididymal or testicular flow. Color Doppler ultrasonography correctly predicted the need for surgery in 5 of 9 operated patients and correctly predicted the outcome in all 32 nonoperated patients. In the two cases of 3 detorsions which were evident in color Doppler ultrasonography was incorrectly diagnosed with testis scintigraphy. Color Doppler ultrasonography is more effective than testis scintigraphy. Results show that color Doppler ultrasonography helps accurately correlate anatomy and perfusion in real time and may prove to be the definitive imaging technique for the diagnostic evaluation of the acute scrotum