Cancer stem cells (CSCs) are a small subpopulation of cancer cells whose resistance to chemotherapy and radiotherapy plays a pivotal role in treatment failure, tumor recurrence and metastasis. Today, the ability of many phytochemicals in targeting of CSCs has been identified. Kaempferol is a plant phytoestrogen that was recognized as a useful agent for targeting cancer cells by apoptosis induction, cell cycle arrest and inhibition of angiogenesis, migration, and invasion of cancer cells. In this study, we compared the effect of docetaxel as a common breast cancer chemotherapy drug and kaempferol on MCF-7 breast CSCs. Results showed that both docetaxel and kaempferol caused a dose-dependent reduction in cell proliferation. Rhodamin 123 dye staining and flow cytometry analysis revealed that after docetaxel and kaempferol treatment, SP cells proportion of MCF-7 decreased to 11.83±2.2% and 3±0.2 5% respectively relative to proportion of untreated control cells (23±3.2%). Moreover, real time PCR results showed that kaempferol treatment of MCF-7 was more effective than docetaxel in down-regulating the CSC-associated markers (i.e. oct4, nanog, abcb1 and aldh1a1). Taken together, these results indicate that kaempferol is an effective anti-CSCs agent, therefore it may be a therapeutic strategy for eradicating breast cancer through the elimination of CSCs.