A 43-year-old infertile man with oligozoospermia and normal serum gonadotropin and cytogenetic findings was treated with follicle-stimulating hormone for 1 year at our institution. Two years later, the patient presented with bilateral palpable testicular tumors. His beta-human chorionic gonadotropin and lactate dehydrogenase levels were elevated. Pathologic examination disclosed a pure seminoma in each testis (pT1N0M0). Adjuvant radiotherapy was administered. The tumors might have been induced by follicle-stimulating hormone treatment. Careful follow-up examination of the testis is necessary in men who have received hormonal treatment for infertility.