This study aimed to extract, characterize and quantify free steroids present on various types of methyl biodiesel produced in the laboratory from different raw materials and a special type of commercial biodiesel. Steroid extraction was performed by sample saponification followed by solvent extraction of insaponificable. Steroid characterization was obtained by gas chromatograph equipped with a flame ionization detector (GC-FID) and by gas chromatograph coupled with a mass spectrometer (GC-MS); steroid quantification was performed by GC-FID. Several different free steroids found present in the biodiesel types were analyzed; some of them were identified as exclusive to certain biodiesel types. It was possible, based on the present free steroid profile analysis methodology, to identify the origin of a commercial biodiesel. Analyses had show that steroid content in biodiesel types ranged from 610 mg kg(-1) in the babassu biodiesel to 3250 mg kg(-1) in the crambe biodiesel. (C) 2014 Elsevier Ltd. All rights reserved.