It has been previously reported that increased expression of coiled‑coil domain containing 34 (CCDC34), a member of the CCDCs family, may promote the proliferation and invasion of bladder cancer cells. However, its role in colorectal cancer (CRC) remains unclear. The present study investigated CCDC34 expression in CRC tissues and determined the association between CCDC34 expression and biological characteristics in patients with CRC. Additionally, the variation of cell activity, apoptosis, invasion and associated mechanisms were evaluated following CCDC34 inhibition in SW620 cells with small interfering RNA (siRNA). The role of CCDC34 in CRC growth, apoptosis and invasion was investigated. In the current study, immunohistochemistry revealed an overexpression of CCDC34 in CRC tissues compared with paracancerous tissue (χ2=29.810; P<0.001). Furthermore, CCDC34 expression was revealed to be associated with tumor invasion depth and lymphatic metastasis (χ2=4.343, P=0.037; χ2=7.915, P=0.005). Additionally, the inhibition of CCDC34 expression in SW620 cells led to reduced tumor cell activity, increased apoptosis rate and reduced invasion ability, and expression of apoptosis and invasion‑associated genes varied simultaneously which demonstrated that B cell leukemia/lymphoma 2, survivin, N‑cadherin, and MMP‑9 were decreased, whereas E‑cadherin increased significantly in cells of CCDC34‑siRNA group compared with the control group (P<0.05). Therefore, CCDC34 may contribute to CRC development by inhibiting apoptosis of cancer cells and promoting invasion.