A case of cystic rectal duplication revealed on day 2 of life by a low intestinal occluding syndrome is reported. Radiologic imaging (ultrasonography, cystography, rectography) showed a large, retrorectal liquid formation in the pelvis and abdomen, with pelvic compression of the terminal alimentary canal and lower urinary tract. Magnetic resonance imaging demonstrated a liquid formation with clearly defined edges and no medullary involvement, thus ruling out the possibility of a previous meningeal hernia. Biological markers were within normal limits. On day 4, a 9 x 6-cm cystic rectal duplication was removed, followed by a temporary colostomy. Pathologic examination demonstrated typical rectal architecture with ciliated cells. Radiologic and clinical findings at 2-month follow-up were reassuring. This case report is exceptional for the following reasons: (1) As a rule, rectal duplications are relatively rare (70 cases reported in the literature); (2) The means of disclosing a neonatal rectal duplication is unusual (4 cases reported in the literature); (3) The volume of the malformation was considerable; and (4) Heterotopic ciliated epithelium was present.