A patient with a sarcoma of the left groin at a site where a prior seminoma had been irradiated is presented. Very few postirradiation sarcomas are described in patients treated with radiation therapy for testicular cancers, even if an increased risk of second malignancies has been reported. In contrast with the highly aggressive clinical course of postirradiation sarcomas, an early discovery of the lesion allowed a radical surgical approach with a presumable cure of the patient. A continuous and precise follow-up of patients irradiated for seminoma is suggested.