Platelet-derived growth factor receptor (PDGFR)‑β is an important tyrosine kinase and its downregulation has been reported to alter the radiosensitivity of glioma cells, although the underlying mechanism is unclear. In order to investigate the effect of PDGFR‑β on the radiosensitivity of glioblastoma, the present study transfected C6 glioma cells with a PDGFR‑β‑specific small interfering (si) RNA expression plasmid, and downregulation of the expression of PDGFR‑β in C6 glioma cells was confirmed by western blotting and immunohistochemical analysis. Clone formation assays and xenograft growth curves demonstrated that PDGFR‑β‑siRNA enhanced the radiosensitivity of C6 glioma cells in vitro and in vivo. Furthermore, MTT and xenograft growth curves demonstrated that PDGFR‑β‑siRNA inhibited the proliferation of C6 glioma cells in vitro and in vivo, and terminal deoxynucleotidyl transferase dUTP nick end‑labeling and immunohistochemical analyses demonstrated that PDGFR‑β‑siRNA induced apoptosis and inhibited the expression of Ki‑67, cyclin B1 and vascular endothelial growth factor in C6 glioma cell xenografts. Taken together, these results suggested that PDGFR‑β may be used as a target for the radiosensitization of glioblastoma.