Niobium oxide impregnated with sodium (Na/Nb2O5) was used as a heterogeneous catalyst to produce biofuel from conventional raw materials, such as soybean oil and beef tallow, and non-conventional feedstocks, including andiroba, babassu, coconut, crambe, macaw palm, palm, palm kernel, and jatropha oils. The trials were performed at fixed conditions using 10% catalyst at 78.5 degrees C under stirring (600 rpm) for 5 h. On the basis of the results generated by gas and liquid chromatographies, high catalytic activity was found for all tested feedstocks, revealing yields higher than 95%. The purity of the ethyl esters was validated by thermogravimetric analysis and nuclear magnetic resonance. The Na/Nb2O5 catalyst performed efficiently, converting the fatty acids present in the lipid raw materials to the ethyl esters, and showed high stability in consecutive batches, generating products that meet the specificity of international standards. The heterogeneity of the catalyst was also confirmed by determining the sodium concentration in both biodiesel and the catalyst after consecutive batch runs.