OBJECTIVE: To determine if there is a seasonal pattern in the occurrence of upper gastrointestinal bleeding in patients with portal hypertension. MATERIALS AND METHODS: All reports on upper gastrointestinal endoscopies at the department of gastroenterology carried out between July 1996 and June 2001 (N=9264) were revised. All cases of upper gastrointestinal bleeding studied by endoscopy were included. The group studied included adults and children considering data on age, sex and reported endoscopic diagnoses. The data was collected and grouped monthly and then regrouped by seasons. The data was processed with Epi Info version 6.0 and analyzed by the chi-square test. RESULTS: Out of all the endoscopies carried out, 11.1% were for upper gastrointestinal bleeding episodes. In total, 114 cases of bleeding associated with portal hypertension were found, these represent 11% of the total number of cases of upper gastrointestinal bleeding. The greatest frequency of upper gastrointestinal bleeding associated with portal hypertension was registered between April and June, which are the autumn months. However, there was no significant difference in comparison with the other seasons of the year. CONCLUSIONS: No seasonal pattern of upper gastrointestinal bleeding associated with portal hypertension was detected.