Background: Ethylenediamine tetra acetic acid (EDTA) is used in several biomedical applications. Aim: The aim of this study was to investigate the effect of EDTA treatment on anticancer efficacy of cisplatin (Cis) against human breast cancer (MCF-7) cells in vitro. Materials and Methods: MCF-7 cells were treated either with Cis, EDTA, or their combination for 24h in vitro. The percentages (%) of the inhibitory, and the median inhibitory concentration (IC50) of EDTA were determined by MTT assay. The % of Cis and EDTA on early and late apoptosis, necrosis, and cell cycle of MCF-7 were assessed by flow cytometry. Results: Our data showed slight antitumor effects for EDTA in vitro. However, Cis/EDTA treatment increased the antitumor efficacy of Cis as evidenced by increasing IC50, and the percentage of MCF-7 mortality. Cis/EDTA co-treatment also increased the % of apoptotic and necrotic MCF-7 cells post 24 h of treatment (26.57 and 16.28%, respectively). Furthermore, this co-treatment arrested MCF-7 cell cycle at G0 phase (32.8%) and G2/M phase (30.25%). Conclusion: Co-treatment of EDTA with Cis increased the anticancer efficacy of Cis.