Introduction: It is well established that SARS-CoV-2 is an enteropathic virus that can lead to diarrhea, nausea, and vomiting, among other GI symptoms. Given the direct impact of SARS-CoV-2 on GI function, combined with the potential of the pandemic to negatively impact the gut-brain axis for some individuals via chronic stress and anxiety, we hypothesized that the prevalence of functional GI disorders (FGIDs) may have increased over time. To test our hypothesis, we conducted a series of cross-sectional surveys using Rome IV questionnaires during the pandemic in nationally-representative samples of >100,000 Americans. Methods: We conducted the initial online survey from 5/3-6/24/2020 during the peak of the initial coronavirus 2019 (COVID-19) wave in the US and followed it with monthly surveys starting in 3/2021 (latter stages of the pandemic). For each survey, a representative adult sample based on US Census age, sex, and region data was recruited. The initial survey included Rome IV questionnaires for irritable bowel syndrome (IBS), chronic idiopathic constipation (CIC), and opioid-induced constipation (OIC) along with demographic and comorbidity questions. In addition, the monthly follow-up surveys also included Rome IV questionnaires for functional dyspepsia, bloating, diarrhea, and unspecific bowel disorder. Our primary outcome was the prevalence of FGIDs and we used logistic regression to adjust for confounding. Differences in prevalence between time periods were considered significant when the 95% confidence intervals (CI) did not overlap. Results: Overall, 103,850 individuals completed the surveys. The Table presents the prevalence of Rome IV FGIDs vs pre-COVID-19 benchmarks reported by Palsson et al. and Sperber et al. (both also used internet-based surveys) in 2015 and 2017, respectively. The prevalence of IBS increased over time; Palsson et al. found that 4.7% (95% CI, 3.8%-5.7%) had IBS in 2015 while we noted that 8.4% (95% CI, 7.5%-9.2%) had IBS in 5/2021. The prevalence of functional dyspepsia also increased, as Sperber et al. reported a rate of 10.1% (95% CI, 8.8%-11.4%) in 2017 vs our finding of 17.7% (95% CI, 16.7%-18.8%) in 5/2021. The prevalence of CIC, OIC, and functional bloating, diarrhea, and unspecified bowel disorder remained stable over time. Conclusion: We found that the prevalence of IBS and functional dyspepsia increased by 75% compared to pre-COVID-19 estimates. We will continue to track the prevalence of FGIDs monthly over the next year to evaluate whether these changes persist.Table 1.: Prevalence of Rome IV FGIDs; data are presented as % (95% CI).