Background and Objective: Childhood constipation can be either due to organic or functional causes without physical and physiological reasons. About 85% to 97% of childhood constipation are functional in nature without any associated organic cause. The aim of the present review was to systematically analyze the prevalence of functional constipation (FC) in children. Methods: Original articles were retrieved by searching in Medline and Cochrane Central Library databases from inception to September 2016 based on Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Around 137 research articles were reviewed and among them 22 articles were chosen for the current review, based on the following criteria: prevalence studies of childhood functional constipation (1) without organic causes, (2) in infants, children and adolescents (0 to 18 years of age) and (3) among general population. Results: The prevalence of FC in children aged below 18 years was found to be ranging from 0.3% to 34.1%. Especially in the case of infants (aged 0-12 months), the range was between 0.3% and 13.7%. The wide range might be due to the variation among the studies in design, ethnicity of the investigated population, and the criteria for diagnosis. Conclusion: It is evident that FC is highly prevalent among children worldwide. However, no studies on Indian population had been found in the specified literature search. Hence, detailed investigations about risk factors and associated complications of FC are needed in the context of Indian scenario. © 2018, Indian Journal of Public Health Research and Development. All rights reserved.