Wild pistachio (Pistacia atlantica F&M.) trees grow in many arid and semi- arid areas of Iran including Khalkhal rigion in Ardabil province. In order to recognize the site demands of this species in Khalkhal forests, six sites (Bane Khalkhal, Kandarag, Mazrae, Nodeh, Jafarabad and Nimehil) were selected and soil properties, climatic data, topoghaphy and growth of wild pistachio were surveyed. Totally, 109 sample plots, each 400m2 with selective sampling method were established. In each sample plot qualitatives and quntitatives characteristics including number of tree, total height, diameter at breast height, basal area, trunk height and crown diameter were recorded. Results showed that wild pistachio is distributed on sites between 760m and 1880 m.a.s.l. with 320mm to 440mm annual precipitation and mean annul temperature between 10.2 ˚C and 17.1 ˚C. The soil of pistachio habitats is shallow, with pH between 7.4 and 8.1, and EC between 0.21 d.s/m and 0.39 d.s/m . Six vegatation types of pure Pistacia, Juniperus-Acer with Pistacia, Rhamnus-Juniperus with Pistacia, Rhamnus-Pistacia, Pistacia-Amygdalus with Paliurus and Juniperus-Pistacia with Amygdalus were recognized. The results of inventory showed that mean dbh of wild pistachio trees varies between 14.6cm in Mazrae and 4.6cm in Nimehil. The mean crown diameter and mean height of trees were calculated of 2.48m and 2.9m, respectively.