Background: Although the use of mechanical bowel preparation (MBP) is still widely promoted as the dogma before patients undergo ileal urinary diversion, an increasing number of clinical trials have suggested that there is no benefit. Thus, we performed a meta-analysis to evaluate the efficacy of MBP in ileal urinary diversion surgery. Methods: A literature search was performed in electronic databases, including PubMed, Embase, Science Citation Index Expanded as well as the Cochrane Library and the Cochrane Clinical Trials Registry, from 1966 to January 1, 2013. Clinical trials comparing outcomes of MBP versus no MBP for ileal urinary diversion surgery were included in the meta-analysis. Pooled odds ratios with 95% confidence intervals were calculated using the fixed- or random-effects models. Results: In total, two randomized controlled trials and five cohort studies were included in this meta-analysis. The primary outcomes, such as bowel leak and bowel obstruction, showed no statistical difference between the two groups. Additionally, the overall mortality rate and death rate related to operation also manifested that MBP does not offer an advantage over the no MBP. Conclusion: This meta-analysis suggests that MBP does not reduce the incidence of perioperative complications in urinary diversion compared with no MBP. However, large randomized controlled clinical trials are needed to confirm this finding.