Economically valuable pistachio nut trees are extensively grown in the Southeastern part of Turkey. A great percentage of the total annual pistachio nut yield in Turkey is obtained from this region. However, fertility aspects of these pistachio trees have not been studied in detail. Thus, there is a need td determine the optimum fertilizer rates to increase the yield and quality of pistachio nuts. Fertilizer trials were conducted on an established 37 year-old-pistachio orchard. Inorganic nitrogen (N) and phosphorus (P) fertilizers were applied in three and two rates, respectively. Potassium (K) was added to all trees as a basal rate. In addition, selected trees received air-dried sheep manure, and additional inorganic macro- and micro-nutrients as a foliar application at three different times during the course of experiment. Fertilizer treatments influenced the fruit yield, productivity, fruit size, percentages of dehisced fruit shell, and nutmeat. Positive effects of these treatments on leaf element content, N, P, and K, were also obtained. Fruit protein and oil contents were not influenced by addition of organic and inorganic fertilizers.