Esophagocoloplasty is a commonly performed procedure for esophageal replacement in children. Traditionally, mechanical bowel preparation (MBP) is performed before this operation. However, this practice has been questioned, initially in adults and now in children. The aim of this study was to evaluate the influence of MBP on esophagocoloplasty in a series of children. Data collected from 164 patients who underwent esophagocoloplasty in the Pediatric Surgery Division, University of São Paulo Medical School, from February 1978 to July 2011 were reviewed for postoperative complications. In 134 patients, at least one kind of MBP was performed before the surgery (PREP group). MBP was omitted in 30 patients (NO-PREP group). There was no statistical difference between the groups in the rates of evisceration, colocolic, or cologastric anastomotic dehiscence and death. However, in the NO-PREP group, the incidence of cervical leakage (6.6%) was significantly decreased in comparison with the classical PREP group (25.3%) (P= 0.03). The results of this study suggest that the omission of MBP has a positive impact on the incidence of postoperative complications in esophagocoloplasty.