BACKGROUND: Early adverse life events (EALs) are associated with irritable bowel syndrome (IBS). Exposure to EALs as assessed by the Adverse Childhood Experiences (ACE) questionnaire is associated with greater disease prevalence, but ACE has not been studied in gastrointestinal disorders. Study aims were to: (i) Estimate the prevalence of EALs in the IBS patients using the ACE questionnaire; (ii) Determine correlations between ACE and Early Trauma Inventory Self Report-Short Form (ETI-SR) scores to confirm its validity in IBS; and (iii) Correlate ACE scores with IBS symptom severity. METHODS: A total of 148 IBS (73% women, mean age = 31 years) and 154 HCs (59% women, mean age = 30 years) completed the ACE and ETI-SR between June 2010 and April 2015. These surveys measured EALs before age 18 in the domains of physical, sexual, and emotional abuse, and general trauma. IBS and abdominal pain severity was measured by a 20-point scale (0 = none, 20 = worst symptoms). KEY RESULTS: The ACE score increased the odds of having IBS (odds ratio [OR] = 2.05, 95% confidence interval [CI]: 1.21-3.48, p = 0.008). Household mental illness (p < 0.001), emotional abuse (p = 0.004), and incarcerated household member (p = 0.019) were significant predictors of IBS. Adverse childhood experiences and ETI-SR scores were strongly correlated (r = 0.59, p < 0.001). ACE, but not ETI-SR, modestly correlated with IBS severity (r = 0.17, p = 0.036) and abdominal pain (r = 0.20, p = 0.015). CONCLUSIONS & INFERENCES: The ACE questionnaire is a useful instrument to measure EALs in IBS based on its use in large studies, its ability to measure prevalence across different EAL domains, and its correlation with symptom severity.