Cinnamon is one of the oldest herbal medicine that has been historically known to possess has anticancer property. In this study, the cytotoxicity of the cinnamon extracts towards human breast cancer cell line (MCF-7) was investigated. Cinnamomum zeylanicum was extracted using Soxhlet and water extraction methods, producing 7.06% and 2.54% of yield respectively. The extracts were analysed using Gas Chromatography/ Mass Spectrometry (GCMS) and it was found that cinnamaldehyde is the major constituents which contribute more than 70% of the major constituents. The cytotoxicity of C. zeylanicum extract against MCF-7 was determined through colorimetric MTT assay at 24 and 48 hours of incubation periods. The IC50 values of Soxhlet extract were 58 µg/ml and 140 µg/ml while the IC50 values of water extract were 9 mg/ml and 4.8 mg/ml, at 24 and 48 hours treatment respectively. In conclusion, C. zeylanicum extracts has been confirmed to have cytotoxic effect towards MCF-7 cell line in different concentrations at two different incubation periods.