Chemotherapy is a potential setting for the treatment of acute monocytic leukaemia (AML). It has recently been demonstrated that statins (hydroxymethyl glutaryl CoA reductase inhibitors) are involved in some antitumor pathways against tumour cells to overcome side effects and increase the efficacy of chemotherapy. The present study was designed to address the molecular and biochemical effects of atorvastatin (ATOR) therapy against the human leukaemia monocytic THP-1 cell line. By in vitro studies, MTT assay was performed to determine the IC50 levels of ATOR against the THP-1 cell line. Also, apoptosis and cell cycle were determined after exposure of THP-1 cells to an IC50 dose of ATOR versus the non-treated THP-1 cells. Flow cytometry analysis showed apoptotic-inducing capacity and arrested the cell cycle in the G2/M phase after the treatment with ATOR. In conclusion, ATOR increases the percentages of apoptotic leukemic THP-1 cells and arrested their cell cycle.