Small cell lung carcinoma (SCLC) is a cancer that shows aggressive behavior, early spread to distant sites, and frequent association with distinct paraneoplastic syndromes. Spontaneous remission of cancer, particularly of SCLC, is a rare biological event. Cases involving spontaneous regression of SCLC were reported, and were associated with paraneoplastic syndromes of the nervous system. This article reports on a 78-year-old man with SCLC in remission, with neurological symptoms. The patient visited the hospital because of generalized weakness, and imaging studies revealed a mass in the lower lobe of the left lung, pathological evaluation showed SCLC. The patient refused oncologic treatment and was treated only with conservative care. In follow-up study the diameter of the mass had decreased from initial 32 mm, 9 months after admission to 20 mm, 17 months after admission to 13 mm. The patient kept complaining of generalized weakness, dizziness, and paresthesia of limbs. We assumed that, in this case, the spontaneous remission of lung cancer was related to the immunologic response directed against the tumor, which is believed to be an important factor in the pathogenesis of paraneoplastic neurologic syndromes.