The safflower (Carthamus tinctorius L.) oil was extracted from the seeds of the safflower that grows in Diyarbakir, SE Anatolia of Turkey. Carthamus tinctorius L. seed oil was investigated as an alternative feedstock for the production of a biodiesel fuel. By traditional solvent extraction, oil was obtained and biodiesel was prepared from safflower by transesterification of the crude oil. A maximum conversion of 93% (oil to ester) was achieved using 100% excess methanol, i.e., molar ratio of methanol to oil is 6:1 and catalyst (NaOH) concentration of 0.5% at 65 degrees C. The viscosity of biodiesel oil is nearer to that of petroleum diesel and the calorific value is about 5.5% less than that of diesel. The quality of biodiesel is most important for engine parts and various standards have been specified to check the quality. The important properties of safflower oil and its methyl ester (biodiesel), such as density, kinematic viscosity, flash point, iodine number, neutralization number, pour point, cloud point, and cetane number, are found out and compared to those of No. 2 petroleum diesel. Fuel properties of methyl esters of Carthamus tinctorius L. oil compare well with ASTM and EN biodiesel standards. The present experimental results support that methyl ester of safflower seed oil can be successfully used as diesel.