Acute Myeloid Leukemia (AML) is a hematopoietic stem cell disorder. Many of the tumor development steps are processes regulated by Ca2+ dependent signaling pathways found in tumor growth. Calcium channels, which can be blocked by pharmacological agents such as verapamil, are important in the regulation of intracellular Ca2+ homeostasis. The failure to stop cell cycle and to achieve programmed cell death are the most important factors in AML or other types of cancers and are considered to be the real cause of cancer. Our aim in this study was to investigate the effect of verapamil on apoptosis and cell cycle in AML cell line, HL-60, using flow cytometry. The effective dose of verapamil was determined as 50 mg / ml by MTT method, and was applied to HL-60 cells, subsequently, they were assessed for apoptosis and cell cycle. After 50 mg / ml of verapamil application, apoptotic cell ratio was found to be 77.7% after 24 hours (p< 0.05). In cell cycle analysis, the ratio of diploid cells decreased in G1 phase and increased in S phase, and the ratio of aneuploid cells decreased in G1 phase (p< 0.05) and increased in S phase (p> 0.05) in verapamil-untreated group when compared to verapamil-treated group.