The Task Committee on Contaminated Ground Water Modeling was approved in September 1990 by the Executive Committee of ASCE's Environmental Engineering Division with the express purpose of assessing widely used models of contaminated ground water. In order to accomplish this, the committee first surveyed the professional community to determine which models are in frequent use; it then classified these models according to a unified set of criteria that they had developed. Based on these criteria, the task committee created guidelines for the application of the models that include the capabilities and limitations of each model. This monograph represents the valuable information compiled by this task committee.