Objective: To investigate the expression of the adaptor protein CARMA3 in cholangiocarcinoma cells and its function. Methods: The expressions of CARMA3 mRNA in cholangiocarcinoma HUCCT1 and RBE cells as well as in normal biliary epithelia cell line HIBEC were determined by qRT-PCR. After silencing the expression of CARMA3 with siRNA technique, the changes in proliferation, apoptosis, cell cycle and abilities of migration and invasion in HUCCT1 and RBE cells were examined by CCK-8 assay, flow cytometry and Transwell assay, respectively. Results: The expression levels of CARMA3 mRNA were significantly increased in both cholangiocarcinoma cell lines compared with normal biliary epithelia cell line HIBEC (HUCCT1 vs. HIBEC: t=5.321, P=0.011; RBE vs. HIBEC: t=5.932, P=0.008). In both cholangiocarcinoma cell lines after silencing the expression of CARMA3, the abilities of proliferation, metastasis and invasion were significantly inhibited, and the G1-phase arrest and apoptosis rates were significantly increased (all P<0.05). Conclusion: CARMA3 is up-regulated in cholangiocarcinoma cells, and its actions may be associated with promoting cell proliferation, migration and invasion, and inhibiting cell apoptosis.