Purpose: The purpose of this study was to retrospectively assess the detectability and enhancement pattern of rectal carcinoid tumors on contrast-enhanced computed tomography colonography (CE-CTC). Methods: The study sample consisted of 12 lesions in nine patients of rectal carcinoid tumors. To evaluate the detectability, two radiologists reviewed axial and 3D images including air enema (AE), virtual endoscopy (VE), and virtual colon dissection (VCD). To determine the contrast enhancement pattern of the tumors, the CT attenuation value of each lesion was measured in three phases. Results: Four of the 12 lesions (33%) were detected on axial images in patients in both the prone and supine positions, the sizes of which were 6 mm or larger. Seven lesions (58%), including the four lesions mentioned above, were detected on 3D images including AE and VE in patients in the prone position, the sizes of which were 5 mm or larger. The ranges of CT attenuation values of the lesions at 40 s, 70 s and 240 s were 112 - 147, 116 - 140 and 82 - 97 HU, respectively. Conclusion: Rectal carcinoid tumors are challenging to detect on CE-CTC. They demonstrated enhancement at the early phase and washout at the delayed phase on CE-CTC.