Abstract: Objective:To investigate the expression and clinical significance of microRNA-30a in renal cell carcinoma (RCC). Methods:The miRNA-30a expression in renal tissues and cell lines was detected using quantitative real-time polymerase chain reac -tion (qRT-PCR), and the relationship between miRNA- 30a expression and the clinicopathological features of RCC was analyzed. The effect of miRNA-30a on cancer cells was evaluated using methyl thiazolyl tetrazolium (MTT) assay. In addition, a bioinformatics algo-rithm was adopted to predict the potential targets of miRNA- 30a. Results: miRNA-30a was downregulated both in RCC tissues and cell lines. Patients with higher miRNA-30a expression exhibited better prognosis than those with lower miRNA- 30a expression. Bioin -formatics algorithm and qRT-PCR both indicated that metadherin (MTDH) was a target of miRNA-30a. Moreover, MTT results showed that miRNA- 30a could inhibit cell proliferation. Conclusion:miRNA-30a was inhibited in renal cancer, and low miRNA-30a expres-sion was associated with poor prognosis. In addition, miRNA- 30a could inhibit the growth of cells through MTDH.