Small cell carcinoma (SCC) of the pancreas is a rare disease, with an extremely poor prognosis; only 24 cases have been reported in the literature. However, as some patients have been successfully treated with combination chemotherapy, it is important to obtain both a definite diagnosis and a precise evaluation of the effect of the treatment. A 69-year-old woman presented with an abdominal tumor and pain. She had been observed for sensory neuropathy and swelling of the pancreatic head by the referring doctor over the previous 9 months. The patient was diagnosed with SCC of the pancreas after surgery and had two courses of combination chemotherapy (cisplatin and etoposide). Initially, the tumor disappeared completely on computed tomography (CT) scans, but she died of disease recurrence 3 months after completing the chemotherapy. Changes in serum neuron-specific enolase (NSE) levels were monitored constantly during the progress of the disease. NSE levels had already increased above the upper limit of normal 8 months before the patient's admission to our hospital, and levels changed concurrently not only with tumor growth but also subsequently with remission and then relapse of the disease after treatment. These results indicate that NSE is a good marker, both as a diagnostic indicator for SCC of the pancreas and as a means of evaluating response to treatment.