Bitter almond (Prunus dulcis var. amara) seed oil was tested as new nonedible feedstock for producing ethylic biodiesel by base-catalyzed transesterification with ethanol. The oil was extracted from bitter almond seed with maximum yield of 42.0 wt%, which can be considered as significant feedstock for biodiesel production. The experimental parameters involved in the optimization process were the type and concentration of the catalyst, ethanol-to-oil molar ratio, reaction temperature, reaction time, and rate of stirring. The maximum yield of biodiesel (97.1% w/w) was obtained using 0.60 wt% KOH, 7: 1 ethanol-to-oil molar ratio, 65 degrees C reaction temperature, 60 min of reaction, and 700 rpm rate of stirring. The fuel properties of the biodiesel were within the acceptable limits prescribed by ASTM D 6751. The H-1 NMR spectroscopy assured the conversion of bitter almond oil into biodiesel. Based on these results, it was concluded that bitter almond seed oil is an acceptable non-edible feedstock for biodiesel production.