The objective of the study was to determine the effect of prebiotics and synbiotics administered in ovo on the 12th day of incubation, on the development of the intestinal villi and the number of goblet cells in the small intestine of broiler chickens on the Ist and the 4th days of life of chicks. Two prebiotics: inulin (PI) or Bi2tos (PB) and two synbiotics: inulin + L. lactis subsp. lactis (SI) or Bi2tos + L. lactis subsp. cremoris (SB) were injected in ovo on the 12th day of embryonic development. The control group of the embryos was injected with physiological saline (C). On the 1st day of life, an increase in the height of the villi in the jejunum was reported as a result of the injection of pre- and synbiotics, moreover an increase in the surface area of the villi in the jejunum and the duodenum in chicks from the SB group was also observed. A stimulatory effect of synbiotics on the morphology of the duodenum and thejejunum was also observed on the 4th dh day after hatching. Conversely, in the ileum, in the SB group, a reduction in the height of villi was found both on thse 1t and thte 4h days of life. In contrast, injection of inulin and synbiotic with the addition of inulin resulted in an increase in the number of goblet cells in the duodenum and the jejunum on thst 1" day of life, and caused a significant decrease on the 4th day after hatching.