The aim of the present study was to determine the effects of dietary administration of a fructooligosaccharide preparation rich in kestose and nestose on growth performance and gastrointestinal parameters in young turkeys. The kestose and nestose preparation was obtained through bioconversion of sucrose using fungi fructosyl transferase and contained in DM 39.9% of kestose, 17.6% of nystose, as well as 26.5% of glucose and 14.7% of sucrose. Three dietary levels of the sum of kestose and nystose (0.3, 0.6, and 1.2%) were fed to growing turkeys for 8 wk. When compared with the control treatment, addition of the kestose and nestose preparation had no effect on feed intake, feed conversion, and BW. The kestose and nestose-supplemented diet, especially the medium level of kestose and nystose, influenced microbial metabolism, especially in the ceca. Compared with the control group, the medium level of kestose and nestose decreased relative weight of gizzard (from 18.67 to 16.51 g/kg of BW) and weight of small intestine tissue (from 23.3 to 19.6 g/kg of BW) and increased weight of ceca digesta (from 3.51 to 4.77 g/kg of BW) as well as activities of microbial beta-glucosidase (an increase from 0.22 to 0.38 U/g) and alpha-galactosidase (an increase from 0.90 to 1.61 U/g), pH of digesta (a decrease from 6.13 to 5.79), concentration of NH3 (an increase from 0.60 to 0.98 mg/g), and concentration of total short-chain fatty acids (an increase from 81.1 to 107.7 micromol/g) in the cecal digesta. A high content of kestose and nestose in the diet caused a decrease in ileal and cecal pH (to 5.42 and 5.49, respectively).