Thirty-three patients with advanced seminoma of the testis underwent serial computed tomography (CT) of the abdomen before, during and after chemotherapy. The immediate post-chemotherapy CT examination showed significant regression in 29 patients and complete resolution in the remaining four (mean regression 70%). Continued CT follow-up at 1 and 2 years revealed further regression of residual masses without further treatment. We recommend that in this group of patients follow-up CT is carried out immediately after chemotherapy and at 1 year. Provided a satisfactory response is observed no further CT assessment is required unless there is clinical suspicion of relapse.