Objective:To investigate the expression and biological function of microRNA 143(miR-143) in bladder transitional cell cancer. Methods:The expression of miR-143 in bladder cancer samples was determined using real-time quantitative reverse transcription (qRT)-PCR. Mature mimics of miR-143 were chemically synthesized and transiently transfected into J82 and T24 cells respectively. Apoptosis and proliferation of the cells were evaluated using flow cytometry and MTS assay. Results:MiR-143 quantification showed low expression of miR-143 in bladder cancer samples. Up-regulation of miR-143 in J82 and T24 cells contributed to cell growth suppression,but not apoptosis. Conclusion:The relative low expression of miRNA-143 may be involved in the tumorigenesis and development of bladder cancer.