Serum testosterone (T), oestradiol (E-2) and sex hormone binding globulin (SHBG) were measured in 84 orchiectomised testicular cancer patients before further treatment and 4 to 6 and 12 to 15 months after therapy. Patients were divided into 3 groups according to treatment: Group 1: cisplatin-based chemotherapy (27 patients); Group 2: abdominal radiotherapy (32 patients); Group 3: no antiproliferative treatment (chemotherapy/radiotherapy) (25 patients). Between 4 and 6 months after antiproliferative treatment, particularly after chemotherapy, a reversible significant increase in E-2 and SHBG was observed. Patients without antiproliferative treatment showed no significant changes in their comparable hormone levels; 15% of all normal T values were associated with elevated levels of SHBG and E-2. Although the aetiology of these hormonal changes remains unknown, they may be related to the clinical symptoms of hypogonadism displayed by 10 to 30% of patients undergoing treatment for testicular cancer.