Biodegradation has been recognized as an important element of natural attenuation of increased organic loading at the seafloor from non-aqueous drilling fluids (NAF) that are associated with drill cuttings discharge. While recognized as an important characteristic of advanced NAF design, measurement of biodegradation properties of base fluids used in NAF presents a technical and regulatory challenge as applied to certain environments. In order to meet this challenge, modification of a standardized anaerobic biodegradation test has been pursued in Brazil with the goal of developing an ecologically relevant and repeatable test that can differentiate between the various NAF technologies. This paper will review the progress to date in developing this biodegradation test for use in Brazil. In particular, the sediment, which is used as the bacteria inoculums, will be compared and contrasted with other natural sediments that have successfully been used in this type of test.