CT colonography (CTC) has been widely used in diagnosis of colon diseases. Computer-aided detection (CAD) automatically detects the locations of suspicious lesions on CTC, and provides radiologists with a second opinion. CAD has the potential to increase radiologists' diagnostic performance in the detection of lesions and to decrease variability of the diagnostic accuracy among readers. The current fundamental scheme, the key techniques used for detection of lesions on CTC, the detection performance, as well as the pitfalls, challenges, and the future of CAD were reviewed in this article.