We report on 6 patients with bilateral testicular germ cell tumors treated by organ sparing surgery. Tumors 6 to 30 mm. in diameter were enucleated, and biopsies of the tumor bed and peripheral parenchyma were taken. Histological examination revealed seminoma in 4 cases, embryonal carcinoma in 1 and a Leydig cell tumor in 1. All patients underwent testicular radiation therapy with 20 Gy. for carcinoma in situ. A testicular biopsy was performed 6 months postoperatively to evaluate therapeutic success. Median followup was 43 months, all patients were free of disease and there was no local recurrence. Luteinizing hormone and testosterone were within the normal range and no androgen substitution was necessary. Our study suggests that organ sparing surgery for bilateral testicular germ cell tumors represents a new therapeutic approach with endocrinological and psychological advantages. In our experience conservative surgery is possible under certain prerequisites, including organ confined tumor without infiltration of the rete testis, obtaining multiple biopsies of the tumor bed and peripheral parenchyma, associated carcinoma in situ treated by radiation therapy and close followup of patients.