Color-coded Doppler ultrasonography is a combination of real-time sonography and duplex sonography for noninvasive imaging of arterial and venous blood vessels. In 40 patients with acute onset of scrotal pain this diagnostic procedure was correlated with the findings at surgical exploration: 11 had testicular torsion, 4 hydatid torsion, 13 spontaneous detorsion, 2 blunt scrotal trauma and 10 epididymitis. For testicular torsion color-coded Doppler ultrasonography had a sensitivity of 82% and a specificity of 100%, and for epididymitis the sensitivity was 70% and specificity was 88%. Color-coded ultrasonography readily demonstrates testicular perfusion. In cases of incomplete or early torsion some residual perfusion may be detected leading to false-negative results. Despite this fact, color-coded Doppler ultrasonography currently is the most valuable diagnostic modality in the evaluation of the acute scrotum.