We have previously demonstrated that androgen-induced proliferation inhibitor (APRIN) expression was upregulated in ventricular septum tissues from patients with ventricular septal defect (VSD). The present study was designed to investigate the effects of APRIN on P19 cell differentiation, proliferation and apoptosis. In this study, we established a stable APRIN-overexpressing P19 embryonal carcinoma cell line that can differentiate into myocardial cells when treated with 1 % dimethyl sulfoxide. Our data showed that mRNA expressions of myocardial cell differentiation-related genes (such as cTnT, α-MHC, GATA4, and MEF2C) in the APRIN-overexpressing P19 cells were downregulated compared to the empty-vector controls. Our findings also indicated that P19 cells overexpressing APRIN had a reduced growth rate and a decreased S phase of the cell cycle. Moreover, the apoptotic rate in P19 cells overexpressing APRIN was significantly higher than that in the controls. In conclusion, our study demonstrates that overexpression of APRIN inhibits differentiation and proliferation and promotes apoptosis in P19 cells, suggesting that APRIN may be involved in the pathogenesis of VSD.