Objective To investigate the efficacy of ultrasound- guided percutaneous microwave ablation (MWA) on renal cell carcinoma (RCC) in elderly patients. Methods Clinical data of 82 RCC patients with 86 lesions ［(mean diameter (2.9±0.9)cm］ treated with water- cooled MWA under ultrasound guidance in our department from January 2006 to October 2015 were collected and retrospectively analyzed. They were at an age of (73.96±7.30) years (ranging from 61 to 87 years), and 58 males were at an age of (74. 0±7. 3) years and 24 females at an age (73. 8±7. 4) years. Enhanced ultrasound and enhanced CT/MRI examination were employed to evaluate the curative effect in 1 d after the treatment, and performed again in 1, 3 and 6 months after operation and every 6 months thereafter. Results The effective rate of treatment was 100% (enhanced images showed complete ablation in 1 month after MWA). The major complications were 3.7% (3/82). The local tumor progression rates were 0. 0%, 1.9%, and 5.2%, respectively for 1, 3, and 5 years after. The 1- , 3- , and 5- year distant metastatic rates were 0. 0%, 1. 6% and 7. 0%, respectively, the corresponding overall survival rates were 98.4%, 96.7% and 91.3%, respectively, and the corresponding disease- free survival rates were 98.4%, 96.6% and 83.5%, respectively. Multivariate analysis showed that age, sex, tumor size, tumor location, ablation time and ablation power had no effect on the overall survival rate in the patients (P>0.05). Conclusion Our study shows that MWA is a safe and effective modality for RCC in the elderly patients.