There is an increased use of scrotal ultrasound in the clinician's office and emergency room for the investigation of scrotal pain. The use of real-time scrotal ultrasound for the diagnosis of testicular torsion has been described in the literature. A false-negative ultrasound examination can postpone the diagnosis of torsion and result in testicular loss. We examined 6 patients 1 day to 18 years old who had subacute testicular torsion with scrotal symptomatology (pain and/or swelling) for longer than 8 hours (range 12 hours to 6 days). Scrotal ultrasound was performed as 1 of the initial tests. A common sonographic pattern was an inhomogeneous testicle with hypoechoic areas alternating with hyperechoic areas and thickening of adjacent scrotal tissue. Another common finding was an edematous hyperechoic epididymis and a small hydrocele. In 4 of the 6 cases these nonspecific findings suggested a misleading diagnosis of tumor or epididymitis and resulted in delay of surgery and testicular loss. Treatment was not delayed in only 2 patients in whom the diagnosis of torsion was made initially by history and physical examination, and ultrasound was done for interest only. Misdiagnosis of intratesticular blood flow and some potential pitfalls of scrotal imaging by color Doppler ultrasound are discussed. We conclude that real-time scrotal sonography can be misleading in cases of subacute testicular torsion and, therefore, it should not be used in this clinical setting.