Background: Breast cancer is one of the causes of mortality in the world. Half of patients with metastatic extend resistance to Tamoxifen and almost all patients eventually become resistant to tamoxifen. Inorder to counteract with the negative effects of tamoxifen, this drug have been placed in combination with the curcumin. Anti-cancer substance which is less toxic than Tamoxifen. In this study, Diblock (Dendrosome) Nano polymer was used in order to tamoxifen packaging along with curcumin. Anti-cancer efficacy of the obtained compound (Diblock, Tamoxifen and Curcumin) was evaluated in Tamoxifen-resistant (TR) MCF-7 cells and Fibroblast cells. Material and Methods: MTT Assay was used to evaluate anti-proliferation effect and drug toxicity.Flow cytometry and Annexin-V-FLUOS were used inorder to assay anti-proliferation effect and induction of apoptosis, respectively. Results: Nano-compound has less toxicity effects on normal cells compared with Tamoxifen and increased apoptosis activity and decreased proliferation in MCF-7 cells which are resistant to tamoxifen. Curcumin and Tamoxifen have more apoptotic potential than Tamoxifen alone, Nano-Tamoxifen or Nano-Curcumin. Conclusion: Results of this study showed that changes in Tamoxifen by curcumin polymeric nanocarrier help to more effective treatment of breast cancer.