The aim of this study was to analyze the data of endoscopy and symptoms in 118 Mexican patients with irritable bowel syndrome (IBS), dyspepsia, non-erosive reflux disease (NERD) and erosive esophagitis (EE). IBS criteria were fulfilling for dyspepsia patients in 47%, for NERD in 48%, and for EE patients in 48% of cases. Esophagitis was present in 42% of patients with IBS and in 45% of patients with dyspepsia. A higher prevalence of hiatus hernia was found in EE vs. NERD. Heartburn and acid eructation were associated with the presence of esophagitis; acid eructation, regurgitation and nocturnal pain with duodenitis; and heartburn and regurgitation with hiatus hernia. Males more frequently reported: mucus in feces, abdominal distension, nausea and gastritis; and women more frequently reported esophagitis and duodenitis. Patients with NERD (OR 2.54, 95% CI 1.08 to 5.99, p=0.04), tenesmus and early satiety, and men had an increase risk for reporting hard or lumpy stools. In conclusion, nearly half of the Mexican patients with NERD, EE and dyspepsia fulfill criteria for IBS. A large number of symptoms were correlated with endoscopy, which can be used to improve the indication of the endoscopy and its implementation in clinical studies.