Color Doppler ultrasonography (US) and testicular scintigraphy were used prospectively to evaluate 28 patients with acute scrotal pain. The results of these imaging studies were correlated with final diagnoses established by means of surgery or clinical follow-up. In all patients, testicular torsion was considered to be a possible diagnosis based on findings from the initial clinical evaluation. Findings from surgery confirmed testicular torsion in seven patients. All cases were correctly diagnosed with color Doppler US. Scintigraphy enabled correct diagnosis of six, but findings were false-negative in one patient with 180 degrees torsion. One patient had a surgically confirmed scrotal abscess that was correctly diagnosed with both color Doppler US and scintigraphy. Findings from clinical follow-up in the remaining 20 patients were consistent with epididymitis, orchitis, or torsion of an appendix testis. There were no false-positive diagnoses of testicular torsion by means of either color Doppler US or scintigraphy in any of these 20 patients. Color Doppler US is at least as accurate as testicular scintigraphy and can function as an effective means of evaluating patients with suspected testicular torsion.