Aim of this study was to determine morphometric differences of fruits between selected sweet chestnuts (Castanea sativa Mill.). The 28 genotypes (referred as CS-01 to CS-28) were introduced by seeds from Czech Republic, Carpathians, Kyrgyzstan. Genotypes of sweet chestnut are grow more than 30 years in Forest-Steppe of Ukraine in the M.M. Gryshko National Botanical Garden of NAS of Ukraine. They are well adapted to the climatic and soil conditions. The fruits were collected at the period of their full maturity (September). The population differs in weight, shape, size and color of fruits. Their morphometric parameters were following: weight from 1.70 g (CS-26) to 18.60 g (CS-20), length from 8.07 mm (CS-28) to 33.39 mm (CS-11), width from 16.34 mm (CS-28) to 40.95 mm (CS-11), thickness from 9.02 mm (CS-26) to 28.70 mm (CS-11) and hilum length from 6.62 mm (CS-26) to 31.30 mm (CS-07), hilum width from 6.50 mm (CS-23) to 19.99 mm (CS-07). The shape index of the fruits was found in the range of 0.81 (CS-20) to 0.98 (CS-12). The shape index of the hilum was found in the range of 1.48 (CS-04) to 2.03 (CS-23). The outcome of the research point to the fact that the genepool Ukrainian sweet chestnut is a rich source of genetic diversity and might be used in selection for creation a new genotypes and cultivars.