This study is to investigate the effect of the geographic variation on the composition of needle oils of Abies bornmuelleriana endemic to Turkey. Samples were taken from the stands distanced up to 500 km from each other. By means of GC-MS/FID analyses, it was found that main compounds making up about 90 percent of the needle essential oils exhibit notable systematic variation depending on the longitude where the trees grow. Among most occurring monoterpenes, the percentages of alpha-pinene and camphene tend to increase in west-east direction. To compensate these increments a decrease was observed in mainly the three monoterpenes, beta-pinene, beta-phellandrene and limonene.