Introduction: Patients with Nasopharyngeal carcinoma (NPC) usually diagnosed at advanced cancer stage and re- current case. Rac1 have become an emerging therapeutic target for metastasis cancer. This gene is critically involved in cell polarization and reactive oxygen species-mediated cell killing. This study aims to investigate the Rac1 activ- ities in NPC/HK1 cell line using siRNA approach and evaluate the calcium deposition profile. Methods: The NPC/ HK1cells were transfected with Rac1-siRNA (siRac1) at concentrations of 50nM, 100nM and 200nM for 24 hours and stained with alizarin red s for calcium mineralization profile. Levels of Rac1 gene expression were measured via qRT-PCR followed by the time dependent assessment for 24, 48 and 72 hours. Results: Findings revealed that siRac1 concentrations of 200nM (p-value