Salinomycin (SAL) has significant therapeutic potential since its antibacterial, antifungal and anticancer activ-ities are highly selective. However, the mechanism that SAL uses to target and eliminate cancer cells is currently not well understood. One limiting factor on studies involving SAL is its low solubility in water, which diminishes its effects in the free form applications. In order to overcome this limitation, in this study we examined the anticancer effect of SAL by using PLGA nanoparticles loaded with SAL (PLGA/SAL) in human osteosarcoma cells (MG-63). High encapsulation efficiency of SAL was achieved as 97.4 +/- 1.87% in the PLGA (65:35, similar to 185 nm) nanoparticles. Controlled and sustained release of SAL was achieved by PLGA nanoparticles for 45 days of in-vitro release study. Our results proved that minimum concentrations of PLGA/SAL nanoparticles were able to decrease proliferation and increase apoptosis of MG-63 cells more than the free form of SAL could. PLGA/SAL nanoparticles enabled the synergistic therapeutic anticancer effect by inducing and inhibiting multiple signaling pathways. They induced caspase-3 expression while suppressing beta-catenin (Wnt/beta-catenin pathway) and c-myc gene expressions in osteosarcoma cancer cells. Results indicated that PLGA/SAL nanoparticles eliminated os-teosarcoma cells more rapidly and efficiently than the free form SAL did.