The acorn (Quercus frainetto L.) kernel oil is extracted from the kernels of the acorn that is grown in Sakarya which is in the Marmara region, Turkey. Acorn kernel oil (AKO) is obtained in 10 wt. %, by solvent extraction. Acorn kernel oil is investigated as an alternative feedstock for the production of a biodiesel fuel. The fatty acid profile of the oil consists primarily of oleic, linoleic, palmitic, and stearic acids. Before processing alkalin transesterification reaction, the high free fatty acid (FFA) of the crude acorn kernel oil is decreased by using acid esterification method. Biodiesel is prepared from acorn kernel (AK) by transesterification of the acid esterified oil with methanol in the presence of potassium hydroxide (KOH) as catalyst. The maximum oil to ester conversion was 90%. The viscosity of biodiesel is closer to that of diesel and the heating value is about 6.4% less than that of petroleum diesel No. 2. All of the measured properties of the produced acorn kernel oil methyl ester (AKOME) are being compared to the current quality requirements according to EN14214 and ASTM D 6751. The comparison shows that the methyl esters of acorn kernel oil could be possible used as diesel fuel replacements.