A Biochemical Methane Potential (BMP) assay provides a measure of the anaerobic digestibility of a given substrate. The use of BMPs provides a relatively inexpensive and repeatable method to make relative comparisons of the anaerobic digestibility and potential biogas production between various substrates. Biochemical Methane Potentials can be used to determine the amount of organic carbon in a given material that can be anaerobically converted to methane and to evaluate potential biogas production efficiency of the anaerobic process on a given material. The information provided by BMPs is valuable when evaluating potential anaerobic substrates and for optimizing the design and operation of an anaerobic digester. This paper describes the BMP assay procedure used in the Agricultural Waste Management Laboratory at Iowa State University for quantifying both biogas production and methane content and it describes how the results can be used.