Polymeric biomaterials are being investigated for the last several years because of their controllable properties. In this study, it was aimed to prepare and evaluate the atRA carrying system using Poly(lactide-co-glycolide) (PLGA). Microparticles were characterized in terms of morphology and encapsulation efficiency. Release studies were performed for the evaluation of drug release rates. Cytotoxicity tests were implemented on MCF-7 Human breast cancer cell line for the investigation of drug and polymer toxicity. The microparticles were found smooth and spherical in shape. However, as the loaded drug amount increased, the sizes of microparticles also increased and the size distribution became less uniform. The sizes of atRA-loaded microparticles ranged between 1-10 mu m. The encapsulation efficiency of atRetinoic acid (all-trans-Retinoic acid) was achieved approximately %90. Approximately, 45% of atRA was released from atRA-loaded microparticles by the end of 4-5 days. Cell growth inhibition was observed after 4 days of incubation of cells with PLGA microparticles.