Homogeneous acid or base catalysts dissolve completely in the glycerol layer and partially in the fatty acid methyl esters (biodiesel) layer in the triglyceride-transesterification process. Heterogeneous (solid) catalysts, on the other hand, can prevent catalyst contamination making product separation much easier. In the present work, the transesterification kinetics of soybean oil with heterogeneous catalysts that display significant Bronstead basicity and their corresponding fatty acid methyl ester yields are presented. It is observed that heterogeneous catalysts require much higher temperatures and pressures to achieve acceptable conversion levels compared to homogeneous catalysts. For some of the solid mixed metal oxide catalysts, a conversion level of 99% was observed. Reaction kinetics were determined for two different temperatures. These catalysts were characterized on the basis of elemental analysis, acidity/basicity, site strength, and surface area.