BACKGROUND: Raw glycerol fractions as the waste material from biodiesel production were investigated for its antioxidant and anticorrosive properties. For comparison raw glycerol fractions and biodiesel fuels together with different oil feedstocks (as an input material for the transesterification process) were measured by means of electron paramagnetic resonance (EPR) spectroscopy. Additionally glycerol fractions were subjected to corrosivity testing (Herbert method). RESULTS: 1,2,3-Propanetriol-containing fractions exhibited high free radical scavenging properties, in comparison with biodiesel and oil material. Additionally, the Herbert test proved the anticorrosive ability of the crude glycerol fractions investigated. Radical scavenging (antioxidant) properties obtained from EPR spectroscopy paralleled the anticorrosive investigations, with samples having the highest quenching abilities giving the best results in the Herbert tests. CONCLUSION: The anticorrosive activity of glycerol fractions examined in this paper generates a new application in lubricant manufacturing. The results show new ways of utilising raw glycerol fraction without very costly and time-consuming purification. (C) 2009 Society of Chemical Industry