Abstract: This study was carried out to produce biodiesel from methyl esters of groundnut (Arachis hypogea) oil and blend with Petrol diesel. The fuel quality of the biodiesel and its blend (B10) was assessed and compared with the ASTM (American Society for Testing and Materials) standards. The groundnut oil was characterized for specific gravity, kinematic viscosity, moisture content, ash content, acid value, free fatty acid, saponification value, iodine value and peroxide value, refractive index and flash point. The biodiesel produced was analyzed for the same parameters including calorific value. The results obtained for the biodiesel showed that while the moisture and ash content were satisfactorily found in trace quantities, the other parameters also had satisfactory results within the specification of 0.88 (specific gravity), 5.16 mm2 sec-1 (kinematic viscosity), 4.96 mg KOH g-1 (acid value), 2.49% (free fatty acid), 244.74 mg KOH g-1 (saponification value), 52.45 mg KOH g-1 (iodine value), 3.23 mEq kg-1 (peroxide value), 1.463 (refractive index), 202°C (flash point) and 39,114.29 J g-1 (calorific value). However, the acid value was found to be higher than the maximum permissible level of 0.8 mg KOH g-1. There was obviously very little change in the parameters of the biodiesel when it was blended except for the flash point which was only slightly below the recommended minimum ASTM value of 130°C. This indicates that the biodiesel produced could be blended with petrodiesel (B10) to give satisfactory fuel with properties not too different from the biodiesel produced.