microRNAs (miRNAs) have been reported to play an essential role in the regulation of brown adipocyte adipogenesis. In the present study, we investigated the role of the miR-106b-93 cluster in the differentiation of brown adipocytes. We found that knockdown of miR-106b and miR-93 significantly induced the expression of brown fat-specific genes and promoted the accumulation of lipid-droplet in differentiating brown adipocytes. In addition, ectopic expression of miR-106b and miR-93 suppressed the mRNA level of Ucp1, a selective hallmark of brown adipocytes. Furthermore, the expression levels of miR-106b and miR-93 are higher in brown adipose tissues of high fat diet-induced obese mice compared to control mice. Taken together, our results identify miR-106b and miR-93 as negative regulators of brown adipocyte differentiation and the miR-106b-93 cluster may play an important role in regulating energy homeostasis. (C) 2013 Elsevier Inc. All rights reserved.