Here we investigate the production and characterization of mono-acylglycerols through the glycerolysis of biodiesel, a methyl ester mixture, obtained from linseed oil. The biodiesel employed was derived from linseed oil through transesterification according to transesterification double step process [1]. The efficiency of H 2 SO 4 , CaO, and NaOH as catalysts was evaluated for the production of monoacylglycerols. The glycerolysis reactions were performed by varying the molar ratio of the reagents (biodiesel:glycerol), the type and amount of catalyst, reaction time and temperature. Systematic evaluation of reaction yield is shown as a function of these parameters. Reaction products were characterized through IR spectroscopy, hydrogen NMR, and the GC techniques. The study of three different catalysts indicated that the most efficient was 5% NaOH in a 1:5 biodiesel-glycerol molar ratio with 10 h reaction time. The reaction reached a maximum of 85% biodiesel conversion with a monoacylglycerol yield of 72% at 1308C.