['Although the rule of 3 is recommended to minimize the risk of perforation when esophageal dilation is performed using bougie dilators, there are no data to validate its use. Our aim was to investigate the association between the rule of 3 and adverse events (AEs) in esophageal dilation.', 'A retrospective chart review in patients who underwent esophageal bougie or balloon dilation between December 1991 and February 2013 at a tertiary hospital was performed. Data collection included patient demographics, stricture and procedural characteristics, AEs, and follow-up. Univariate logistic regression models were used to assess the risk of AEs and perforations.', 'A total of 297 patients (median age, 63 years; 60% men) underwent 2216 esophageal bougie or balloon dilations. Major AEs occurred in 22 (1%) dilation sessions, including 11 (0.5%) perforations, 4 (0.2%) fistulas, 3\xa0(0.1%) hospitalizations for pain management, 2 (0.09%) clinically significant hemorrhages, 1 (0.04%) fever, and 1 (0.04%) tracheoesophageal voice prosthesis leak. Mean duration of treatment was 43.2 months (standard deviation, 47.7 months). Most strictures were benign (n\xa0= 275; 93%) and complex in nature (n\xa0= 198; 67%). Non-adherence to the rule of 3 occurred in 190 (13%) dilations with bougie dilators. Non-adherence was not associated with a higher rate of major AEs (1/190, 0.5% vs 15/953, 1.6%; P\xa0= .18) and perforations (0/190, 0% vs 7/952, 0.7%; P\xa0= .18). Gender, complex strictures, location of the stricture, type of dilator, and additional interventions were also not associated with major AEs or perforations. However, malignant strictures were associated with an increased risk of major AEs (odds ratio, 3.5; 95% confidence interval, 1.1-12.0) and perforations (odds ratio, 8.3; 95% confidence interval, 2.2-31.9).'] Does non-adherence to the rule of 3 increase the risk of adverse events in esophageal dilation?