Objective:To investigate the effects of acrylamide on apoptosis and miR-21 expression in SH-SY5Y neuroblastoma cells. Methods:Cell viability of SH-SY5Y cells treated with different concentrations of acrylamide for 24 hours was measured by MTT. Hoechst 33258 staining was used for the determination of cell apoptosis;miR-21 expression was detected by real-time PCR; the expression levels of PTEN,p-AKT,AKT,Bcl-2,Bax,caspase 9 and caspase 3 were examined by Western blot. Results:Acrylamide exposure resulted in decreased viability and induction of apoptosis of SH-SY5Y cells in a dose-dependent manner. miR-21 expression was downregulated by acrylamide. Meanwhile,acrylamide increased the expression levels of PTEN,Bax,caspase 9 and caspase 3,and decreased p-AKT and Bcl-2 expression in SH-SY5Y cells. Conclusion:Acrylamide induces apoptosis of SH-SY5Y cells via mitochondrion pathway,and down-regulation of miR-21 may be involved in the regulation of apoptotic process induced by acrylamde.