Objective: Several evidences have suggested that PPARγ activation might affect neural differentiation. To investigate the role of PPARγ on neural precursor cells and mature neurons, embryoid bodies (EBs) were treated after retinoic acid and PPARγ agonist (Rosiglitazone) and antagonist (GW9662). To evaluate the efficiency of embryoid formation of mouse embryonic stem cells, expression of nestin, MapII and GFAP were evaluated. Data indicated that nestin expression on was not influenced by PPARγ agonist, while, PPARγ antagonist decreased expression of this neural precursor marker. Assessment of mature neuron and glial markers was also not affected by agonist while a significant reduction in expression of MapII and GFAP upon treatment with the PPARγ antagonist. This observation was further confirmed by staining of β-tubulin III and GFAP staining of EBs. In addition treatment with the PPARγ antagonist resulted in significant reduction on the size of EBs. Materials and Methods: For formation of neural precursor cells, embryoid bodies were derived from mouse embryonic stem cells by 2days culture in hanging <font><font>drop</font></font>s followed by 4 days in suspensions in presence of retinoic acid. For differentiation and formation of mature neural cells, the embryo bodies were plated in neurobasal medium. To investigate the role of PPARγ on neural precursor cells and mature neurons, EBs treated with RA and PPARγ agonist (Rosiglitazone) and antagonist (GW9662) . In this stage expression of Nestin as specific NPCs marker, MapII (mature neuron marker) and GFAP (mature glial marker) evaluated in 6th and 14th day, respectively. Result: Data indicated Nestin expression did not be influenced by PPARγ agonist(Rosiglitazone) while, PPARγ antagonist(GW9662) decrease expression of this neural precursor marker. Also Mature neuron and glial cells were formed from these NPCs did not significant illustrate in expression of MapII and GFAP while, PPARγ antagonist caused decrement in both expression of these markers. Conclusion: Several evidences suggest that PPARγ activation might affect neural differentiation and PPARγ stimulated neurite extension in neuroblastoma cell line. Our results demonstrated increment of PPARγ expression in neurogenesis is due to RA treatment and PPARγ is maybe critical role in neural differentiation of mESCs during neural precursor cell formation.