The effects of Enterococcus faecium NCIMB 10415 on the development of pancreas and small intestine, and on activity of some pancreatic digestive enzymes were investigated in broiler chickens. In total, 168 Ross 308 female broiler chickens were used. The chickens were assigned to two groups, control and experimental. Enterococcus faecium NCIMB10415 was added by 1.23x10(9) CFU/kg to the diet of the experimental group animals for a period of 42 days. Feed intake and body weights of animals were recorded weekly and feed efficiency was calculated. On days 0, 7,14, 21, 28, 35 and 42 twelve chickens from each group were sacrificed and the development of pancreas and small intestine was investigated. Activities of a-amylase, lipase, trypsin and chymotrypsin in pancreas and contents of duodenum, jejunum and ileum were also determined. Body weight, feed intake and feed efficiency were not significantly different between treatments. Enterococcus faecium NCIMB10415 had no effect on weight and allometric growth of pancreas, duodenum, jejunum and ileum. Activities of a-amylase, lipase, trypsin and chymotrypsin in the intestinal content were lower in the probiotic group (P<0.05) than in the control group. The results of the study suggest that the supplementation of Enterococcus faecium NCIMB10415 to the diet of broilers at a level of 1.23x109 CFU/kg does not affect fattening performance and does not have a negative effect on the development of the gas-trointestinal tract. However, it might affect enzyme biosynthesis and secretion from pancreas indirectly.