The aim of this study was to compare stabilities of bio-oils and fuels that are extracted from low value feedstock (animal-based fat) to those of more conventional feedstocks (rapeseed oil). The biofuel feedstocks chosen represent the current situation of decentralized biodiesel production in Finland. The Finnish biodiesel production is based on the low value feedstocks that are mainly by-products of small-scale industry (e.g. food industry). The stabilities of these biofuels were measured by determining their Oxidation Stability Index (OSI) using the Rancimat method. The stabilizing effect of synthetic antioxidants (BHA and IONOL BF 1000) for oils and ester-type fuels used was determined. With different antioxidants, there were considerable differences between the stabilities of the oils and fats as well as of the esters made from these feedstocks.