BACKGROUND AND AIM: Knowledge regarding prognosis and factors influencing the clinical course of functional constipation in children is important to enable general practitioners and paediatricians to give accurate patient information, to compare treatment strategies, and identify children with high risk for unfavourable outcome. The objective of the study was to investigate and summarize the quantity and quality of evidence on prognosis of childhood constipation with and without treatment and its predictive factors. METHODS: An extensive literature search in MEDLINE and Embase was performed to identify prospective follow-up studies evaluating the prognosis or prognostic determinants of functional constipation. Methodological quality was assessed using a standardised list. Results on prognosis of constipation were statistically pooled, and the influence of prognostic factors was summarised in a best evidence synthesis. RESULTS: The search strategy resulted in a total of 2882 abstracts. Only 14 publications met our inclusion criteria, of which 21% scored high methodological quality. Included studies showed large heterogeneity in study populations and outcome measures. Without regard to these differences, 49.3% +/- 11.8% of all of the children followed for 6 to 12 months were found to recover and taken off laxatives. The percentage of children who were free from complaints, regardless of laxative use, after 6 to 12 months was 60.6% +/- 19.2%. There is substantial evidence that defecation frequency and a positive family history are not associated with recovery from constipation. CONCLUSIONS: The few studies published on prognosis of childhood functional constipation and predictive factors showed large heterogeneity and poor methodological quality. Overall, 60.6% of children are found to be free from symptoms after 6 to 12 months. Recovery rate showed no relation with defecation frequency or positive family history. Based on the present literature, we are unable to identify a group of children with high risk for poor prognosis.