Recently, the impact of microRNAs (miRNAs) has been identified in hepatocellular carcinoma (HCC), this study was designed to assess the effects of miR-124-3p and midazolam (MDZ) in HCC with the involvement of PIM-1.,HepG2 human HCC cells were selected for our study, which were treated with different concentrations of MDZ. The gain- and loss-of-function experiments were performed to elucidate the migration, invasion, proliferation, colony formation ability, cell cycle, and apoptosis of HepG2 cells upon treatment of MDZ, miR-124-3p mimics, or miR-124-3p inhibitor. The expression levels of miR-124-3p, PIM-1, Bax, Bcl-2, P21, and Ki-67 in HepG2 cells were assessed by reverse transcription quantitative polymerase chain reaction and western blot analysis. Moreover, HepG2 cell growth in vivo was measured by subcutaneous tumorigenesis in nude mice, and the target relation between miR-124-3p and PIM-1 was evaluated using dual luciferase reporter gene assay.,We have found that after treated with overexpression of miR-124-3p and MDZ, there exhibited elevated miR-124-3p, declined expression of PIM-1, attenuated migration, invasion, proliferation and colony formation ability, and promoted apoptosis of HepG2 cells. Additionally, it could be observed that the tumor volume and weight were all reduced upon treatment of overexpression of miR-124-3p and MDZ. Meanwhile, the results in the HepG2 cells that treated with down-regulated miR-124-3p were the opposite. Furthermore, PIM-1 was found to be a target gene of miR-124-3p.,Our study found that MDZ could inhibit proliferation and accelerate apoptosis of HCC cells by elevation of miR-124-3p and suppressing PIM-1, which may be an effective method in the treatment of HCC.,© 2019 International Union of Biochemistry and Molecular Biology.