The fatty acid composition and some physical properties of nuts of Turkish tree hazels were investigated. Average nut weight, diameter, shell thickness, percent kernel, and moisture content were determined. Oil content ranged between 64.48% and 71.92%. Oleic and linoleic acids was the predominant fatty acids, together representing 91.7% of the total. The amount of palmitic and stearic acids was low while palmitoleic, margaric, margaroleic, linolenic, arachidic, and gadoleic acids were present in trace amounts. This is the first report on the fatty acid composition of Turkish tree hazel.