Uzun is one of the major pistachio varieties of Turkey. In this study conducted in seven different locations of the Buyuk Menderes River Basin of western Anatolia (Turkey), some biochemical and fruit quality traits were assessed. Biochemical contents such as protein, fat, dry matter and ash contents, unsaturated and saturated fatty acid compositions in this variety were determined based on locations over a period of 2 years. Biochemical composition such as protein, fat, dry matter and ash contents differed significantly by locations (P < 0.05). The mean protein content ranged from 23.2%-31.7%. The mean fat content varied from 46.8%-66.5%. The unsaturated fatty acid composition as percent showed averagely a range of 72.2-75.0 for oleic acid, 11.2-13.1 for linoleic acid, 0.27-0.34 for linolenic acid, 0.21-0.28 for arachidic acid, 0.40-0.43 for gadoleic acid and 0.11-0.14 for behenic acid depending on locations. The saturated fatty acids as percent composed a range of 0.06-0.08 in myristic acid, 8.25-9.52 in palmitic acid, 0.59-0.76 in palmitoleic acid, 0.05-0.07 in heptadecanoic acid and 2.36-3.71 in stearic acid. The contents of saturated fatty acids (palmitic, palmitoleic and stearic) except for myrictic and heptadecanoic acid, and all unsaturated fatty acids (oleic, linoleic, linolenic, arachidic and behenic) except for gadoleic acid also differed significantly by locations (P < 0.05). Consequently, the biochemical composition was significantly affected by different growing areas. (c) 2006 Elsevier Inc. All rights reserved.