We report a case of a patient presenting with a small cell cancer of the lung which was limited to the thorax and treated by radiotherapy and chemotherapy in March 1983. In december 1986 a contralateral small cell cancer still limited to the thorax was discovered and treated with success using chemotherapy. Nevertheless the complete remission obtained did not last beyond 16 months and the patient died in september 1988. We discuss the possibility of late metastasis but we think the occurrence of a second small cell cancer is the more plausible hypothesis.