Limbic encephalitis is an unusual presentation of paraneoplastic syndrome. We report a case of small cell lung carcinoma associated with limbic encephalitis. A 67-year-old man presented with convulsions, memory impairment, and neuropsychiatric disturbances as initial symptoms. Subsequently, small cell lung carcinoma was diagnosed by bronchoscopic biopsy. The cerebrospinal fluid studies, electroencephalography, and magnetic resonance imaging findings had distinctive features compatible with paraneoplastic limbic encephalitis. The neuropsychiatric symptoms improved significantly after six cycles of systemic chemotherapy and adjuvant radiotherapy, resulting in partial remission of the tumor. A follow-up computed tomography scan of the head showed no evidence of intracranial metastasis 7 months after the diagnosis of cancer. Limbic encephalitis may be an initial manifestation of lung cancer. Greater awareness for diagnosis and early treatment of the primary tumor offers the best chance for improvement in patients with lung cancer presenting with limbic encephalitis.