Background: Few data are available on the prevalence of erosive and severe esophagitis in Western countries. Objective: To retrospectively determine the prevalence and the factors predicting erosive esophagitis and severe esophagitis in a large series of endoscopies in Spain. Design: Retrospective observational study. A multivariate analysis was performed to determine variables predicting severe esophagitis. Setting: Databases of 29 Spanish endoscopy units. Patients: Patients submitted to a diagnostic endoscopy during the year 2005. Interventions: Retrospective review of the databases. Main Outcome Measurements: Esophagitis severity (graded according to the Los Angeles classification) and associated endoscopic findings. Results: Esophagitis was observed in 8.7% of the 93,699 endoscopies reviewed. Severe esophagitis (LA grade C or D) accounted for 22.5% of cases of the disease and was found in 1.9% of all endoscopies. Incidences of esophagitis and those of severe esophagitis were 86.2 and 18.7 cases per 100,000 inhabitants per year respectively. Male sex (OR 1.89) and advanced age (OR 4.2 for patients in the fourth age quartile) were the only variables associated with severe esophagitis. Associated peptic ulcer was present in 8.8% of cases. Limitations: Retrospective study, no data on individual proton pump inhibitors use. Conclusions: Severe esophagitis is an infrequent finding in Spain. It occurs predominantly in males and in older individuals. Peptic ulcer disease is frequently associated with erosive esophagitis. © 2011 Ponce et al.