Objectives: The direct mechanism for exacerbation of kidney damage caused by obesity has not been clearly elucidated. Ring finger protein 20 (RNF20), an E3 ubiquitin ligase that plays various roles such as adipogenesis and DNA damage response, is known to regulate lipid metabolism in the kidney, but studies on lipid metabolism in exacerbation of chronic kidney disease have not been conducted. Methods: After palmitic acid (PA) treatment in human kidney epithelial (HK2) cells, cytotoxicity was confirmed using cell viability assay. Lipid accumulation was performed with oil-red o staining, and changes in protein expression related to lipid metabolism and fibrosis were confirmed by western blot.   Results: PA treatment induced lipid accumulation and cytotoxicity in HK2 cells. In addition, RNF20 expression was decreased in lipid accumulation-induced cells, and expression changes of lipid metabolism-related proteins PPARa and SREBP1 were observed. To investigate the relationship between lipids and fibrosis, TGF-beta and PA were co-treated. As a result, it was confirmed that lipid accumulation was increased compared to the single treatment group, and decreased fatty acid oxidation and fibrosis-related proteins were increased. Conclusions: RNF20 is involved in PA-induced lipid accumulation and lipotoxicity in renal tubular cells. When fibrosis is accompanied, RNF20 activates pro-fibrosis factors by regulating proteins involved in lipogenesis and fatty acid oxidation. Therefore, it means that RNF20 is an important factor in the process of renal fibrosis aggravation by lipids in chronic kidney disease.