Background/Aims: Chicago classification version 4.0 (CCv4.0) of esophageal motility disorders developed a more stringent diagnostic criteria for ineffective esophageal motility (IEM) than version 3.0. We studied the implications of the new diagnostic criteria on the prevalence of IEM, and clinically characterized and compared the population of patients who no longer meet diagnostic criteria for IEM to those who retain the diagnosis. Methods: We included all consecutively performed high-resolution esophageal impedance manometries from 2014 to 2021. Three cohorts of patients with IEM were created: Patients with IEM by Chicago classification version 3.0 (CCv3.0; CC3 group), by CCv4.0 only (CC4 group), and by CCv3.0 who are now considered normal (Normal group). Demographics, manometric and reflux parameters, and clinical outcomes were compared. Results: A total of 594 manometries were analyzed. Of those, 66 (11.1%) met criteria for IEM by CCv3.0 (CC3), 41 (62.0%) retained an IEM diagnosis using CCv4.0 criteria (CC4), while 25 (38.0%) patients no longer met criteria for IEM (Normal). The CC4 group had higher esophageal acid exposure, especially supine (% time - 18.9% vs 2.2%; P = 0.005), less adequate peristaltic reserve (22.0% vs 88.0%;P = 0.003), and higher Demeester score (49.0 vs 21.2; P = 0.017) compared to the Normal group. There was no difference in bolus clearance between the groups. Conclusions IEM under CCv4.0 has a stronger association with pathologic reflux, especially supine reflux, and inadequate peristaltic reserve, but impairment in bolus clearance is unchanged when compared with IEM diagnosed based on CCv3.0. Further studies are required to determine the implications of these findings on management strategies.