Abstract : The U.S. Army Center for Environmental Health Research (USACEHR), a detachment of the U.S. Army Medical Research Institute of Chemical Defense, in collaboration with Battelle, has recently evaluated the use of 10 sensor technologies for rapid identification of toxicity in drinking water. The objective was to evaluate the ability of these sensors to respond rapidly (in less than an hour) to the presence of 12 industrial and agricultural chemicals. USACHER coordinated the participation of laboratories with applicable sensor technologies and, together with Battelle, developed an experimental plan, managed the preparation and distribution of the contaminant solutions to the contributing laboratories, came to consensus with the laboratories on how to perform the sample analysis and data reporting, and evaluated the results. This report describes the experimental work that was performed and then describes the results obtained from each of the participating sensors. Test results will be used to help select toxicity sensors to be used to evaluate Army drinking water supplies. This activity supports Army Technology Objective IV.ME.2004.03, "Environmental Sentinel Biomonitor (ESB) System for Rapid Determination of Toxic Hazards in Water".