The exoskeleton of a cockroach plays a major role in protecting it from pathogenic microbes. It is well known that the main component of the exoskeleton is the chitin which is considered the source of chitosan. This study aimed at investigating the anticancer activity of chitosan prepared from the American cockroach. Chitosan was prepared and characterized with solubility in 1% acetic acid and Fourier transform infrared spectroscopy (FT-IR) analysis. The cytotoxicity of chitosan was investigated against Hepatoblastoma (HepG2) and Breast cancer (MCF7) cell lines by the MTT assay. The cytotoxicity has a positive relationship with the chitosan concentration. The half-maximal growth inhibitory concentrations (IC₅₀) were 329 and 195 µg/ml with HepG2 and MCF7, respectively. Therefore, Chitosan may be a potential natural compound for the treatment of human hepatoblastoma (HepG2) and breast cancer (MCF7).