The scrotum is a superficial structure and clinical examination is frequently not enough for making a specific diagnosis. In acute scrotal pain US can confirm the presumptive clinical diagnosis and provide additional relevant information. In testicular torsion, color-Doppler imaging has a central role since it has become possible to identify it at early stage by showing absence of perfusion in the affected testis before any gray-scale abnormality. Scintigraphy remains a satisfactory alternative in evaluating testicular torsion and should be used when color Doppler is inadequate, raising doubts about the suspected torsion. Diagnosis of torsion of testicular appendages is particularly difficult. Ischemic infarction shows a characteristic pattern at gray-scale and color Doppler imaging, whereas hemorrhagic ischemia may require MRI. Inflammatory diseases of the scrotum can be easily investigated by echo color Doppler and conventional radiography, and CT can be particularly useful in the detection of gas bubbles. In scrotal trauma, scrotal hematoma, hematocele, intratesticular hematoma, and testicular rupture can be identified using gray-scale US with very good reliability. Magnetic resonance imaging is indicated when a small tear of tunica albuginea is suspected but not visualized on US.