The Standard Evaluation Procedure (SEP) describes the procedures used by EPA to evaluate studies on the rate of degradation of pesticide residues in the laboratory under anaerobic conditions in soil. The SEP provides a data reviewer with important guidance in determining the acceptability of an anaerobic soil metabolism study. Details of the proper study design are outlined and the relevance of each aspect of the study design pertinent to pesticide degradation under anaerobic conditions is explained. The information is to be used by the reviewer as guidance in determining study acceptability. The document outlines the general theory of pesticide degradation and provides an overview of the methods used for calculating pesticide degradation rates and half-lives. Important points to consider in assessing the data and in drawing conclusions about the degradation rate of pesticide residues under anaerobic conditions in soil are discussed.