Scrotal pain has a variety of causes, which can lead to considerable morbidity and mortality if left undiagnosed. It is important to establish the aetiology to ensure appropriate investigation and management. Causes of acute scrotal pain have been identified by various retrospective reviews in children: in a review of 238 cases, 16 per cent were caused by testicular torsion, 46 per cent by torsion of the testicular appendage and 35 per cent by epididymitis. Given the proportion of patients who have testicular torsion, early assessment of scrotal pain is critical. [With links to the evidence base]