The worldwide epidemic of obesity demands novel and more effective therapeutic approaches. Fat cells are at the core of energy metabolism trying either to cope with a positive energy balance by hypertrophy and hyperplasia of energy storing white adipocytes or to counteract obesity by the induction of non-shivering thermogenesis in energy combusting brite/brown adipocytes. However, the comprehensive regulatory network of adipocyte formation remains to be elucidated. MicroRNAs are an emerging class of important regulatory determinants in many biological processes and diseases, including adipocyte formation and obesity. In this review, microRNAs governing the formation of white, brite and brown adipocytes as well as candidates with impact on obesity are overviewed, concluded with recommendations for further research that considers prerequisites for successful therapeutic applications.