Each year, testicular torsion affects one in 4,000 males younger than 25 years. Early diagnosis and definitive management are the keys to avoid testicular loss. All prepubertal and young adult males with acute scrotal pain should be considered to have testicular torsion until proven otherwise. The finding of an ipsilateral absent cremasteric reflex is the most accurate sign of testicular torsion. Torsion of the appendix testis is more common in children than testicular torsion and may be diagnosed by the "blue dot sign" (i.e., tender nodule with blue discoloration on the upper pole of the testis). Epididymitis/orchitis is much less common in the prepubertal male, and the diagnosis should be made with caution in this age group. Doppler ultrasonography may be needed for definitive diagnosis; radionuclide scintigraphy is an alternative that may be more accurate but should be ordered only if it can be performed without delay. Diagnosis of testicular torsion is based on the finding of decreased or absent blood flow on the ipsilateral side. Treatment involves rapid restoration of blood flow to the affected testis. The optimal time frame is less than six hours after the onset of symptoms. Manual detorsion by external rotation of the testis can be successful, but restoration of blood flow must be confirmed following the maneuver. Surgical exploration provides definitive treatment for the affected testis by orchiopexy and allows for prophylactic orchiopexy of the contralateral testis. Surgical treatment of torsion of the appendix testis is not mandatory but hastens recovery.