Poly(lactic acid)(PLA) is the most generally chosen bio-polymer because of its lower price and commercially availability in the market. Although PLA has high strength and modulus, its inherent brittleness and low toughness limits its usage [1]. Poly(buthylene adipate-co-teraphthalate) (PBAT), is an aliphatic-aromatic copolyester that can be used to toughen PLA [2]. Due to incompatibility between PLA and PBAT, in the absence of a compatibilizer they exhibit poor mechanical properties [3]. Polyhedral oligomeric silsesquioxanes (POSSs) are new generation organic/inorganic hybrid materials that have an inorganic Si-O case with functional organic groups. Epoxy functionalized POSS nanoparticles are potential nanoparticles that can be used to compatibilize PLA/PBAT blends since epoxy group can react with -COOH groups in a wide temperature range [4]. In this study, it was aimed to observe the potential of epoxy-POSS nanoparticles to be used as a compatibilizer for PLA/PBAT blends. Three different types of epoxy-POSS types were used. Blends were prepared by melt compounding process. In order to characterize properties of blends, morphological, mechanical, thermo-mechanical, thermal and rheological tests were examined. The results showed that epoxy-POSS types can be used as a compatibilizer for PLA/PBAT immiscible blends. Acknowledgement: This study is financially supported by TUBITAK (Grant Number: 115M576) References [1]A. L. M. Siz, N. A. Ibrahim, W. M. Z. W. Yunus, Iran Polym J. 2013(22) 101-8. [2] N. Zhang, Q. Wang, J. Ren, L. Wang, J. Mater. Sci., 2009(44), 250-6. [3] M. Nofar, A. Maani, H. Sojodi, M. C. Heuzey, P. J. Carreau, J.Rheol. 2015(59-2), 317-33. [4] W. Zhang, B. X. Fu, Y. Seo, E. Schrag, B. Hsiao, P. T. Mather, N. Yang, J. Sokolov, Macromol., 2002(35),8029-38.