Introduction: Gastric hypomotility (GH) is a major complication of atrial fibrillation (AF) ablation. We aimed to clarify whether additional cryoballoon ablation (CBA) of the left atrial (LA) roof is associated with GH. Methods and Results: This study included 54 patients with non-paroxysmal AF who underwent CBA for pulmonary vein isolation and of the LA roof line. GH was defined according to the results of esophagogastroscopy performed 2 days after ablation. GH was observed in 10 patients. There were significant differences in LA diameter (LAD), right inferior pulmonary vein (RIPV) diameter, and the height of the LA roof from the point where the LA posterior wall and esophagus make contact between patients with (GH+) and without GH (GH–) (LAD: 41.0 [36.3–41.8] mm vs. 46.5 [42.8–50.0] mm, p<0.01; RIPV diameter: 19.7 [19.0–20.5] mm vs. 23.2 [21.2–24.9] mm, p<0.01; height of LA roof: 5.7 [5.1–6.1] mm vs. 8.8 [7.1–11.2] mm for, p<0.01, respectively). Multivariate analysis revealed that LA roof height was a predictor of GH. Moreover, Patient Assessment of Upper Gastrointestinal Disorders-Symptom Severity Index (PAGI-SYM) scores increased significantly 1 week after ablation (from 1.0 [0.0–2.8] to 5.0 [3.0–11.0], p=0.03) in patients with GH. Conclusion: The height of the LA roof may be a predictor of GH after CBA of the LA roof line. Additionally, GH-related symptoms may still appear 1 week after ablation.