The function of lncRNA CRNDE and its role in prostate cancer (PC) remains unclear. The aim of this study was to determine the expression level of lncRNA CRNDE in PC tissues and to elucidate its role in PC. The expression levels of lncRNA CRNDE were measured by quantitative reverse transcription polymerase chain reaction. The role of lncRNA CRNDE in PC cells was studied using loss-of-function assays . Cell proliferation, migration, invasion, and apoptosis were assessed via Cell Counting Kit-8, colony formation, flow cytometry, wound healing, and transwell chamber assays. A luciferase reporter assay was used to characterize the interaction between lncRNA CRNDE and miR-146a-5p. In PC tissues, the expression level of lncRNA CRNDE was upregulated. Moreover, knockdown of lncRNA CRNDE suppressed PC cell proliferation and migration and induced apoptosis . miR-146a-5p was verified as a direct target of lncRNA CRNDE. Moreover, the inhibition of miR-146a-5p partially counteracted the effects of lncRNA CRNDE on PC cell proliferation, migration, and invasion. In conclusion, lncRNA CRNDE may serve as a cancer promoter in PC by targeting miR-146a-5p. Therefore, lncRNA CRNDE could be a promising target for the clinical treatment of PC.