Thirty-five patients were examined 6-11 years after operation for torsion of the testis. Loss of testicular tissue was significantly associated with long preoperative duration of symptoms and with low postoperative sperm counts. The sex hormones were normal in the majority of patients but there were significantly higher levels of both FSH and LH in the group of patients with symptoms exceeding 8 hours. There was also a higher prevalence of abnormal semen quality in the same group. Furthermore, FSH and LH levels correlated significantly to the duration of symptoms and correlated inversely to the sperm count and concentration. Measurement of carnitine levels in seminal plasma, as a sign of vas deferens obstruction or dysfunction of epididymis, and of autoantibodies against spermatozoa revealed no significant findings.