Background: During radiation therapy, stromal cells surrounding the tumor (e.g mesenchymal stem cells) may affect the treatment outcomes. We aimed to investigate the effects of gamma radiation on the mRNA expression of cytokines, DNA damage and population doubling time (PDT) of adipose-derived mesenchymal stem cells (ASCs). Material and methods: ASCs were enzymatically extracted from breast tissue and exposed to different doses of 5, 10, and 30 Gy of gamma radiation. The capability of ASC proliferation, the level of DNA damage, and the expression of angiogenic and immunosuppressive factors were evaluated using PDT, comet assay, and qRT-PCR, respectively. Results: Gamma irradiation of ASCs with different doses of 5, 10, and 30 Gy significantly increased PDT and DNA damage in a dose-dependent manner (P< 0.05). A dose of 5 Gy caused a significant increase in SDF-1 whereas a 10 Gy dose significantly increased the expression of both SDF-1 and IL-10 (P< 0.05) in ASCs. Conclusion: Results indicate that different doses of gamma irradiation may induce angiogenesis and immunosuppression in ASCs via different cytokines which may affect the radiotherapy outcome.