Renal cell carcinoma (RCC) is the most aggressive type of genitourinary cancer and highly resistant to current available therapies. In this work, we investigated the effects and mechanism of anti-parasitic agent ivermectin in RCC. We show that ivermectin significantly inhibits proliferation and induces apoptosis in multiple RCC cell lines that represent different histological subtypes and various mutation status. Importantly, ivermectin is significantly less or ineffective in normal kidney cells compared with RCC cells, demonstrating the preferential toxicity of ivermectin to RCC. Ivermectin also significantly inhibits RCC tumor growth in vivo. Mechanistically, ivermectin induces mitochondrial dysfunction via decreasing mitochondrial membrane potential, mitochondrial respiration and ATP production. As a consequence of mitochondrial dysfunction, oxidative stress and damage is detected in ivermectin treated RCC cells and xenograft mouse model. The rescue of ivermectin's effect by acetyl-L-Carnitine (ALCAR, a mitochondrial fuel) or antioxidant N-acetyl-L-cysteine (NAC) confirms mitochondria as the target of ivermectin in RCC cells. Compared to normal kidney cells, RCC cells have higher mitochondrial mass and respiration, and ATP production, which might explain the preferential toxicity of ivermectin to RCC. Our work suggest that ivermectin is a promising candidate for RCC treatment and targeting mitochondrial metabolism is an alternative therapeutic strategy for RCC. (C) 2017 Elsevier Inc. All rights reserved.