Widespread use of trichloroethylene (TCE) in the U.S. has resulted in its frequent detection in soil and groundwater. TCE can become a health hazard after being processed in the human liver; or reductive dehalogenation in the environment may result in production of vinyl chloride, a known carcinogen. This has generated a high degree of interest in efficient and cost-efficient technologies that can be used to remediate soil and groundwater contaminated with TCE. The purpose of the paper is to present and discuss relevant physicochemical properties and reactive mechanisms of TCE, and to delineate and discuss promising remediation methodologies that have been proposed and/or demonstrated for restoring contaminated subsurface environments. The information in the article has been funded wholly or in part by the U.S. EPA under contract No. 68-C8-0058 to Dynamac Corporation; it has been subjected to the Agency's peer and administrative review process and approved for publication.