Body fat mass is closely associated to diseases related to obesity. MicroRNAs (miRNAs, miR) are important regulatory molecules that function as post-transcriptional gene regulators of adipocyte development. In the current study, we revealed that reduced expression of miR-199a-3p in adipose tissue resulting from high fat diet (HFD)-induced obesity in mice. Overexpression of miR-199a-3p promoted adipocyte proliferation by regulating the expression of regulating factors of the cell cycle. Furthermore, miR-199a-3p blunted lipid accumulation in 3T3-L1 adipocytes. This was accompanied by a marked decrease in the expression of adipocyte-specific genes involved in lipogenic transcription, fatty acid synthesis, and fatty acid transportation. Furthermore, the fatty acid oxidation process was enhanced. Luciferase activity assays confirmed that miR-199a-3p regulates adipocyte differentiation by directly targeting the 3'-untranslated region (3'-UTR) of stearoyl-CoA desaturase (SCD). Moreover, miR-199a-3p regulates fatty acid composition by decreasing the ratio of unsaturated fatty acids (UFAs) in adipocytes transfected with miR-199a-3p mimics. These results suggest that miR-199a-3p may promote adipocyte proliferation, while also repressing adipocyte differentiation by down-regulating SCD and changing fatty acid composition during adipogenesis. (C) 2017 Published by Elsevier Inc.