Leucine-rich pentatricopeptide repeat motif-containing protein (LRPPRC) is a multifunctional protein involved in the mitochondrial gene expression and function, cell cycle progression, and tumorigenesis. However, the functional role of LRPPRC in prostate cancer (PCa) has not yet been elucidated. In this study, two PCa cell lines were examined to determine the effects of LRPPRC on cell proliferation, invasion, and apoptosis in vitro. Our results showed that the expression levels of LRPPRC were significantly decreased in the two PCa cell lines after transfection with small interfering RNA (siRNA)-LRPPRC. Knockdown of LRPPRC by siRNA significantly inhibited the invasion and promoted the apoptosis of PCa cells. In addition, downregulation of LRPPRC expression resulted in the reduced expression of Bcl-2, upregulation of Bax, and cleaved caspase-9 and caspase-3. Taken together, these results show that the downregulation of LRPRPC expression induces apoptosis through the mitochondria-mediated pathway in PCa cells. These experimental data seem to suggest that LRPPRC plays a critical role in the development of PCa, and its inhibition could present a potential molecular approach for the treatment of PCa.