Production of biodiesel through optimized base-catalyzed transesterification of safflower oil was investigated. Various experimental variables, such as the oil/methanol molar ratio (1:3, 1:6, 1:9, 1:12, 1:15, and 1:18), temperature (30, 45, and 60 degrees C, rate of stirring (180, 360, and 600 rpm), catalyst concentration (0.25, 0.50, 0.75, 1.00, 1.25, and 1.50%), and catalyst types (KOH, NaOH, KOCH3, and NaOCH3) were adopted. An oil/methanol molar ratio of 1:6, sodium methoxide catalyst concentration of 1.00%, mixing intensity of 600 rpm, and reaction temperature of 60 degrees C offered the best safflower oil fatty acid methyl esters (biodiesel) yield (98%). Characterization of the fatty acid methyl esters (FAMEs) was accomplished by gas-liquid chromatography (GLC). Fuel properties, such as density, specific gravity, kinematic viscosity, high heating value, cetane number, flash, cloud, pour, and cold filter plugging points, copper strip corrosion, acid value, and sulfur, water, and ash contents of the biodiesel produced were compatible with American Society for Testing and Materials (ASTM) D 6751 and EN 14214 specifications, where applicable. However, the cold filter plugging, cloud, and pour points were somewhat higher than the conventional diesel fuel. Results of the present investigation demonstrated that the biodiesel produced through methanolysis of safflower oil under a given set of experimental conditions has fuel properties quite comparable to those of mineral diesel and thus may be explored for potential applications in compression-ignition engines.