A 74-year-old woman with left-sided heart failure was admitted to our department with abnormal shadow in the right lung. Chest X-P and CT scans showed a tumor shadow measuring 2.5 cm in the right lower lobe and mediastinal lymphnode swelling. Cytological examination of needle biopsy specimen revealed small cell carcinoma (cT1N2M0). Elevations of tumor marker, NSE and CEA were noticed at 11.8 and 12.7 ng/ml, respectively. Considering complications including renal insufficiency and heart failure in the case, 2 courses of oral etoposide (25 mg/body) for 21 consecutive days were performed. The tumor shadow decreased remarkably in size and complete response (CR) was obtained. Side effects were all tolerable. A pharmacokinetic study of etoposide revealed serum etoposide levels of more than 1.0 microgram/ml on day 15. These results suggest that oral etoposide administration is an effective regimen in small cell lung cancer patients associated with renal insufficiency.