A case of multilocular cystic renal cell carcinoma is reported, in which nephron-sparing surgery was done using microwave tissue coagulation. A 37-year-old man was referred to our outpatient clinic for a multilocular cystic tumor, 4.5 cm in diameter, in the middle-lower portion of the right kidney, which was detected by ultrasound during a health checkup. The patient had been found to have the same cystic mass on a CT done during another health checkup 1.5 years before. The tumor showed no growth during the 1.5-year period. With a diagnosis of multilocular cystic renal cell carcinoma, T2N0M0, in situ non-ischemic tumor enucleation was done using a microwave tissue coagulator (Microtaze, Heiwa Electronics Industry Inc., Tokyo). Operation time was 150 minutes and blood loss was 135 cc. The histological diagnosis was renal cell carcinoma, T2N0M0V0, cystic type, clear cell subtype, grade 1. Diagnostic imaging done postoperatively showed no sign of damage to renal function. In this report, the characteristics of multilocular cystic renal carcinoma are reviewed from the literature, and the advantages of nephron-sparing surgery for this type of renal tumor are discussed. In addition, an operative technique of tumor enucleation used in this case and the characteristics of Microtaze are introduced.