We describe a case of paratesticular leiomyosarcoma occurring in a 37-year-old man, 34 years after receiving wide excision and irradiation for fibrosarcoma of the left thigh. To our knowledge, this is the first report of irradiation-associated testicular leiomyosarcoma of a Chinese man, who presented a progressively enlarged non-tender left scrotal mass. He died from metastatic disease 20 months after radical orchiectomy with adjuvant radiation therapy and systemic chemotherapy.