BACKGROUND: A new classification criterion for diagnosing ineffective esophageal motility (IEM) was proposed at the 2018 Stanford symposium, but limited data exists about the utility of this criterion. METHODS: We conducted a cross-sectional study among 3826 patients treated at the Institute of Gastroenterology and Hepatology, Hanoi, Vietnam, between March 2018 and May 2020. Patients were classified as having normal motility, mild IEM, severe IEM, or absent contractility based on the Chicago classification version 3.0 and the new IEM criterion (severe IEM was defined as having >70% ineffective swallows). We examined the association between these 4 motility subgroups and the presence of erosive esophagitis and Barrett's esophagus, using multivariate logistic regression analysis. RESULTS: The mean age of the study sample was 44.7 years and 66.3% were women. The prevalence of symptoms, hiatal hernia, and -positive patients was similar in the 4 study groups. The 4-second integrated relaxation pressures and lower esophageal sphincter resting pressures were lower in patients with severe IEM and absent contractility. Severe IEM and absent contractility, but not mild IEM, were significantly associated with Los Angeles (LA) grade B-D esophagitis (relative risk ratio [RRR] for severe IEM 1.81, 95% confidence interval [CI] 1.17-2.80; and RRR for absent contractility 2.37, 95%CI 1.12-5.04). None of the hypomotility subgroups were associated with LA grade A esophagitis and Barrett's esophagus. CONCLUSIONS: Patients with severe IEM have a high prevalence of severe erosive esophagitis. These findings suggest the need for a more meaningful classification criterion for IEM.