There is little cytological information for Pistacia species in the literature and-they are old or require confirmation. This study aims to adapt a chromosome count procedure for Pistacia species and to determine chromosome numbers of four Pistacia 2 species in root tip cells. Chromosome counts were performed for P. vera L., P. terebinthus L., P. atlantica Desf. and in a new species P. eurycarpa Yalt., which have been characterized at the molecular level. Dehulled Pistacia nuts were stratified and treated with 500 ppm GA(3) and then germinated on plates. Growing root tips were used for counting at c-metaphase of mitosis cells. A good chromosome counting procedure was established for Pistacia species that provided well-spread and well-stained chromosome at metaphase of mitosis. Chromosome numbers of all four Pistacia species were found to be 2n = 30. Chromosome numbers of P. atlantica and P. eurycarpa (syn. P. atlantica subsp. kurdica) species are reported here for the first time as 2n = 30. This study provides important information on pistachio cultivars/rootstocks for breeders and cytogeneticists.