In a retrospective study of patients treated for germ cell tumours, the authors found seven patients with primary extragonadal tumours in the retroperitoneum. These tumours are, in terms of histology, identical with germ cell tumours of the testis. The disease manifests itself by pain in the kidney region, palpable abdominal mass, weight loss, fever, and gynaecomasty. The diagnosis was confirmed histologically by examining tissue specimens obtained by probatory laparotomy and from the supraclavicular lymph nodes. The choice of therapy and prognosis of disease depend on the histological evidence. Orchiectomy is unnecessary provided both testes are clinically unaltered.