A systematic review and meta-analysis reported that the prevalence of biopsy-proved celiac disease was four times more in patients meeting diagnostic criteria for irritable bowel syndrome (IBS) than in control individuals without IBS. To assess the prevalence of celiac disease in unselected adults meeting diagnostic criteria for IBS, the reviewers searched few sources for case series and case-control studies reporting the results of serologic tests for celiac disease. For all 14 included studies, prevalence of positive serologic test results for celiac disease and biopsy-proved celiac disease were extracted and pooled. These findings were also compared between patients with IBS and control individuals, using an odds ratio (OR) and 95% confidence interval (CI). Of the 4204 individuals enrolled in the identified studies, 2278 (54%) met diagnostic criteria for IBS. The pooled prevalence of positive immunoglobulin A (IgA)–class antigliadin antibodies (AGA) was 4.0% (95% CI, 1.7% – 7.2%), the prevalence of positive endomysial antibodies (EMA) was 1.63% (95% CI, 0.7% – 3.0%), and the prevalence of tissue transglutaminase (tTGA) was 4.1% (95% CI, 1.9% – 7.0%). For biopsy-proved celiac disease, the pooled prevalence was 4.1% (95% CI, 1.9% – 7.0%). In patients meeting diagnostic criteria for IBS compared with control individuals without IBS, pooled OR for positive IgA-class antigliadin antibodies was 3.40 (95% CI, 1.62 – 7.13), pooled OR for either positive EMA or tTGA was 2.94 (95% CI, 1.36 – 6.35), and pooled OR for biopsy-proved celiac disease was 4.34 (95% CI, 1.78 – 10.6). Limitations of this study include problems with the method of the type of studies included, possible spectrum bias in case-control studies, too few test results in some cases to allow meaningful pooling of data, and possible selection bias in studies based in secondary care.