Aims: The investigation of fecal retention using objective and patient-friendly tools, rather than the diagnosis of constipation, might be important in the management of overactive bladder (OAB) in children. The present study aimed to evaluate the incidence and grade of fecal retention in children with OAB and to determine the effectiveness of laxative treatment for fecal retention in the management of OAB in children. Methods: This study included 88 children with OAB aged 5-15 years. Fecal retention was defined as type 1/2 feces (Bristol stool form scale) or a Leech score above eight points, and constipation was determined according to the ROME III criteria. Among the 88 children, 71 with fecal retention or constipation were treated with oral laxatives (polyethylene glycol 3,350/4,000 or lactulose) for 2 weeks, and the responses to the treatment were assessed. Results: Among the 88 children, 63 (71.6%) had a Leech score above eight points as assessed by plain abdominal radiography, 52 (59.1%) had type 1/2 feces (Bristol stool form scale), 24 (27.3%) had functional constipation and only 6 (6.8%) had none of either. Among the 71 children who received laxative treatment for 2 weeks, 58 (81.7%) reported an improvement in OAB symptoms. Additionally, the number of children with a Leech score above eight points was significantly higher in the good response group than in the poor response group (P = 0.014). Conclusion: Investigation of fecal retention with the Leech scoring system and laxative treatment might be helpful in the management of OAB in children. (C) 2016 Wiley Periodicals, Inc.