A recent breast cancer operation appears to have become more simplified, and we may cure an early stage breast cancer without a surgery in the future. This study was approved by our institutional review board and all patients received the study information. We started a radiofrequency ablation (RFA) in April 2008 for breast cancer patients without extensive ductal spreads and the tumor size of 2 cm or less measured by magnetic resonance imaging (MRI). At first, we performed five patients from a clinical viewpoint of technique and safety. All cases were performed safely. There was no complication such as burns. At the mid observation period of 22 months in average (range 21-24), no local recurrence and distant metastases were occurred after RFA. Cosmetic after RFA was excellent in all cases.