ABSTRACT: Oxygenated additives have been the subject of much research because they notably improve the fuel characteristics and combustion performance. Moreover, there is a tendency to use oxygenated additives derived from biomass. In the case of glycerol, previous studies have shown that oxygenated compounds are generated by dehydration, decomposition and isomerization reactions from glycerol and its intermediaries, where the selected route of these reactions depends on the type of catalyst used. In this work, the liquid phase obtained during the catalytic glycerol decomposition at 400 °C using a basic catalyst was characterized by GC and GC–MS. This phase is constituted mostly by highly oxygenated compounds of known energetic use. After a drying process, the effect of the glycerol condensates as an additive in diesel–biodiesel (B5) engines at the 0.2% (v/v) concentration was evaluated. The physical properties of the fuel and the mechanic, thermodynamic, and environmental performance of the stationary diesel engine were analyzed in the current study. The presence of the additive decreased the pour point of diesel and the amount of particulate matter generated during combustion.