Scrotal ultrasonography has many indications. Evaluation of testis masses, hydroceles, and extratesticular structures are the most common indications. Color Doppler ultrasound has made assessment of scrotal blood flow possible. This enables the sonographer to make specific diagnoses in cases of acute scrotal pain. Other indications include evaluating infertile men, searching for an undescended testis, and evaluating the traumatized scrotum.