Abstract: The aim of the present study was to investigate comparatively embryonic development of the small intestine in two boiler strains by means of histological, histochemical and immunohistochemical methods. In the experiments, 125 fertile eggs from each of two commercial broiler strains were used. On the days 11, 13, 15, 18, 20 and 21 of incubation, intestinal tissue samples were taken from 10 live embryos of each strain. Rapid histological, histochemical and immunohistochemical changes occurred in the small intestine during the investigation period. Although, the intestinal villi were rudimentary and uniform on the days 11, 13 and 15, they were at different developmental stages on the days 18, 20 and 21 of incubation. Mucin containing goblet cells first appeared at 13th day of incubation. Majority of the goblet cells contained acidic mucin at 18th day of incubation. Goblet cell density increased on the days 20 and 21 of incubation. Enteroendocrine cells were first seen at 13th day of incubation. Their number was 1-4 in the majority of the villi on the day 18 of incubation and remained relatively constant thereafter. Most of the villous epithelial cells were proliferative cells. A few apoptotic cells were also observed towards the apex of the villi on the days 20 and 21 of incubation. Intestinal development patterns of both strains were quite similar. When considering the importance of embryonic development of small intestines to the chick growth and development, the data may contribute to comparative studies on the performance traits of these broiler strains.