We have been monitoring the health and behavior of 97 search and rescue dogs deployed on 9/11/01 to the World Trade Center and Pentagon disasters and 55 non-deployed control search and rescue dogs. This study has been ongoing since just after the disasters occurred. Currently, a veterinary epidemiologist is analyzing the first 5 years of bloodwork data, and a board certified radiologist is reviewing the first 5 years of chest radiographs to determine if any changes have occurred or any trends exist. To date, 32 deployed dogs and 15 control dogs enrolled in the study have died. The proportion of deceased deployed dogs is not significantly different than the control group. The rate of cancer in deceased deployed dogs is not different than the rate of cancer in deceased control dogs either. In order to further evaluate the effect of deployment on rate and onset of cancer in these dogs, it is essential to continue to monitor the bloodwork and radiographs of these dogs and the controls throughout their natural lifespan.