The prognosis of small-cell lung cancer remains poor and it is speculated that small-cell lung cancer patients with end-stage renal failure undergoing hemodialysis have a poorer prognosis. In this article, we present a Japanese woman with extensive small-cell lung cancer with end-stage renal failure undergoing hemodialysis who received multiple courses of chemotherapy. Although she achieved long-term survival of more than 2 years, the last-line chemotherapy, consisting of irinotecan, induced grade 4 febrile neutropenia and her performance status deteriorated even with a reduced dose according to the analysis of UDP-glucuronosyltransferase 1A1. We also conducted a pharmacokinetic analysis of irinotecan, the resulting values of which were much higher than in previous reports. Although further studies are needed, chemotherapy for small-cell lung cancer patients should not be withheld just because they are undergoing hemodialysis; however, chemotherapy should be performed more carefully because more severe toxicities can occur than expected.