miRNAs have been reported to be involved in multiple cellular processes and the tumorigenesis of various cancers. miR‑15a‑5p (also termed miR‑15a) has previously been determined to be upregulated in renal cell carcinoma (RCC) by microarray profile. However, the expression and function of miR‑15a‑5p in RCC remain to be validated. In the present study, reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR) was performed to detect the expression levels of miR‑15a‑5p in RCC tissues and cells. The expression level of miR‑15a‑5p was upregulated or downregulated by transfecting synthesized miR‑15a‑5p mimics or inhibitors. The MTT assay, CCK‑8 assay, Transwell assay, wound healing assay, Hoechest 33342 staining and flow cytometry were conducted to investigate the role of miR‑15a‑5p in RCC. The results of the RT‑qPCR demonstrated that miR‑15a‑5p was upregulated in RCC tissues and ACHN, 786‑O and 769P RCC cells compared with paired normal tissues and HEK‑293T cells. miR‑15a‑5p was observed to be associated with RCC cell proliferation, migration, invasion and apoptosis. The results demonstrated that miR‑15a‑5p may be important as a tumor promoter in RCC. To the best of our knowledge, the present study is the first to describe miR‑15a‑5p as a tumor promoter in RCC. Further research will be performed to investigate the underlying signaling pathway of miR‑15a‑5p and the potential role of miR‑15a‑5p as a biomarker for early detection, prognosis prediction and a therapeutic target of RCC.