Objective: A polymer-based nanoparticle was constructed to target sorafenib delivery to colorectal carcinoma cells and decrease the side effects of the drug. Methods: Sorafenib-loaded nanoparticles (S-NPs) based on PEG-PLGA were prepared using a double emulsion solvent evaporation method. The properties of S-NPs were evaluated and then their effects on the viability of colorectal cancer cells and normal human cells were assessed. The mechanism of S-NP internalization was explored using cellular uptake assays and in vitro fluorescence confocal imaging. Acute toxicity of sorafenib on its own or within S-NPs was assessed in mice. Results: S-NPs showed high drug loading and entrapment efficiencies, they did not cause extensive hemolysis, and they efficiently inhibited growth of colorectal cancer cell lines and human umbilical vein endothelial cells. S-NPs showed lower acute toxicity than the free drug. Conclusions: Loading sorafenib into nanoparticles can enhance its uptake by colorectal cancer cells and decrease its acute toxicity.