Biodiesel, one of green fuels and clean energies, is compatible with traditional petroleum-based diesel and both can be completely blended without any stratification. Biodiesel was prepared from corn by transesterification of the crude oil with methanol in the presence of NaOH as catalyst. Transesterified corn oil has better properties globally because it has the greater monounsaturated content. Determination of blend levels is one important issue to the quality control of biodiesel due to the increase of biodiesel-diesel blends commercialization. The objective of this study was to characterize how the key fuel properties changed when the commercial petroleum diesel fuel was blended with methyl ester produced from corn oil. In the present study, commercially available diesel fuel was blended with the biodiesel prepared from corn oil. The blends of biodiesel petroleum diesel were prepared on a volume basis. The important properties of corn oil methyl ester (biodiesel)-diesel fuel blends, such as density and kinematic viscosity, are found out and compared to those of No. 2 petroleum diesel, ASTM, and EN biodiesel standards.