Acute nontraumatic scrotum represents one of the most important emergencies in the male population. Etiology of the acute scrotum greatly varies, but the most common causes include testicular torsion and inflammatory disease. Currently, the most successful diagnostic imaging is ultrasound integrated by the application of color power Doppler. A very important finding is the detection of presence/absence of intratesticular blood flow for the early identification of testicular torsion. This pictorial essay aims to illustrate the various causes of acute nontraumatic scrotum by using color power Doppler ultrasound imaging, based on a retrospective analysis of 768 cases performed at our Level I trauma center between January 2005 and June 2006.