The existence of Brunner's glands (BGs) in the duodenal submucosa is uncontestable, but their exact distribution along the full extent of the duodenal wall is unknown. Objective: To verify the BGs distribution along the human duodenum. Material and method: Twenty normal duodenums were examined. Two samples were removed from each of the four anatomical portions of the duodenum using a scalpel, in such a way that the whole circumference of each portion was excised. Sections were prepared and stained with hematoxylin-eosin. Twelve microscope fields were examined on each duodenal section. The mean numbers of glandular points per field were computed and compared, for the 12 microscope fields of each duodenal section examined. Results: The first duodenal portion presented large quantities of BGs in all of the fields examined. The second duodenal portion also showed the presence of BGs in all the fields examined, albeit in smaller quantities than in the first portion. In the third duodenal portion, BGs were present in six of the duodenums examined. In the fourth duodenal portion, there was a minimal quantity of glands, all located in only ten of the duodenums studied. Conclusions: BGs are present in the submucosa of all duodenal portions, with the greatest concentration in the first portion. Their concentration decreases significantly in the second portion of the duodenum. Furthermore, they become even fewer in number in the third portion and are minimally present in the fourth portion