OBJECTIVE: To determine the optimal age for screening endoscopy on patients with dyspepsia without alarm symptoms to avoid missing gastric cancer. METHODS: A Cross sectional study was performed (2001-2005). 285 cases of patients with dyspepsia and gastric cancer were found at Arzobispo Loayza National Hospital. Cumulative age frequencies and percentiles were used to determine the optimal age for screening endoscopy. Both groups, with and without alarm symptoms were compared using the chi-square test for categorical data. Continuous data was expressed as mean (SD) and was compared with the t- test. Significant values of p were specified as <0.05. RESULTS: A total of 32,388 upper endoscopic procedures in dyspeptic patients were performed and 285 cases of gastric cancer were diagnosed, 45 cases of them not featuring any alarm symptoms were found. There were no differences in cumulative frequency between the <35 and <40 years old, with a frequency of 0.29 and 0.20 per 1000 endoscopies, respectively. If the age of 40 had been taken as the optimal age for screening, 4 cases of gastric cancer (8.9%) would have been missed (one case per year approximately), one case would have been an early gastric cancer. The 5th percentile was 30.3 years old and the 10th was 39.4. If the age of 45 had been taken as the optimal age for screening, 6 (15%) cases of gastric cancer would have been missed and 12 (27%) cases if the age was 55 years old. There was no statistical difference between gender, age and duration of dyspepsia. On the other hand, relations between type of dyspepsia (ulcerative), type of lesion, position, histology and stage of gastric cancer for both groups were found. CONCLUSION: It's recommended that the optimal age for endoscopic screening for gastric cancer in dyspeptic patients without alarm symptoms for both genders, should be over 40 years old.