ATPase family AAA domain-containing 2 (ATAD2) has been identified as a critical modulator involved in cell proliferation and invasion. The purpose of this study was to explore the expression of ATAD2 in CRC tissues as well as its relationship with degree of malignancy. Data containing three independent investigations from Oncomine database demonstrated that ATAD2 is overexpressed in CRC compared with normal tissue, and similar result was also found in 32 pairs of CRC tissues by qPCR. The protein expression of ATAD2 was examined in six CRC cell lines and 300 CRC specimens. The results showed that high expression of ATAD2 was significantly correlated with tumor size (P < 0.001), serum CEA (P = 0.012), lymph node metastasis (P = 0.018), liver metastasis (P = 0.025), and clinical stage (P = 0.004). Kaplan-Meier method suggested that higher ATAD2 protein expression significantly associated with the overall survival (OS) of CRC patients (P < 0.001) and was an independent predictor of poor OS. Functional studies showed that suppression of ATAD2 expression with siRNA could significantly inhibit the growth in SW480 and HCT116 cells. These results indicated that ATAD2 could serve as a prognostic marker and a therapeutic target for CRC.