Background <p>Bloating/abdominal distension is a common gastrointestinal symptom. However, the abnormal endoscopy results associated with bloating/abdominal distension and its influencing factors in outpatients remain unclear.</p> Methods <p>This multicenter cross-sectional study was conducted in 100 tertiary care hospitals nationwide and involved the use of a mobile applet to complete questionnaires to record the medical history of outpatients with bloating/distension. This was followed by an analysis of the upper and lower gastrointestinal endoscopic detection results and the factors influencing them. Finally, the transition from the Rome III to Rome IV criteria was explored to assess changes in the diagnostic landscape in patients with chronic bloating/distension.</p> Results <p>A total of 1481 patients with chronic bloating/distension were included. The rate of abnormal endoscopic examination of upper gastrointestinal tract (GI) symptoms was greater than that of lower GI symptoms (16.6% vs. 11.5%, <i>P</i> &lt; 0.05). Logistic regression revealed that alarm signs were the only risk factor associated with abnormal upper GI findings (<i>P</i> = 0.040; OR = 1.753; 95% CI: 1.026–2.995), and a disease duration greater than 6 months was a protective factor for positive lower GI endoscopy findings (<i>P</i> = 0.036; OR = 0.590; 95% CI: 0.360–0.967). Comparative analysis revealed diverging diagnostic trends under the Rome IV criteria. Specifically, PDS diagnoses decreased by 6.1% and IBS by 7.7%, whereas FC, U-FDB and FAB/D increased by 1.3%, 2.7% and 10.5%, respectively. EPS rates remained stable, with DGBI overlap diagnoses increasing by 1.2%.</p> Conclusions <p>The positive endoscopic finding of upper GI bloating/distension was greater than that of lower GI, and the risk factors associated with positive findings were alarm symptoms but had limited sensitivity/specificity. The transition from the Rome III to Rome IV criteria changed the diagnostic landscape for patients with chronic bloating.</p>