To identify changes in incidence, presentation, management and outcome, 670 patients with torsion of the spermatic cord presenting in Bristol between 1960 and 1984 have been reviewed. Among the susceptible population of 150,000, the annual incidence of torsion has increased fourfold from 11.2 cases between 1960 and 1964 to 42.8 cases between 1980 and 1984. Throughout this period greater than 90 per cent of patients have been managed by general surgeons. Patients aged between 12-18 years comprised 62 per cent but 20 per cent were 21 years or older. Torsion was commoner in the cold months, 24 per cent of cases occurring during December and January (chi 2 = 30.26, P less than 0.01). When acute torsion was relieved within 12 h of the onset of symptoms only 4 per cent of affected testes were considered non-viable, but beyond this time 75 per cent of patients received orchidectomy. Overall, 238 of 624 (38 per cent) acutely twisted testes were found to be infarcted at operation, and a further 35 patients (6 per cent) had marked testicular atrophy on review 3 months later. The testicular salvage rate has steadily improved from 45 per cent in the years 1960-64 to 67 per cent in 1980-84. Much of the increased incidence of testicular torsion is likely to reflect a greater awareness of the condition by general practitioners. It has been more than matched by an improvement in testicular salvage rate because of earlier referral.