The population-based cohort study is the best design for assessing the possible health effects resulting fromliving in contaminated sites. The ERAS (Epidemiology,Waste disposal, Environment and Health) Project was established to study the health of people living in close proximity to urban solid waste treatment (RU) plants in Lazio. It was conducted using an integrated approach, which consisted in studying mortality and hospital discharges of residential cohorts surrounding urban waste treatment plants. The level of exposure of each address was assigned using pollution dispersion models and studying the effects on mortality and hospital discharges. Further studies were conducted on residents of areas adjacent to waste disposal sites (includingMalagrotta in Rome), incinerators andmechanical biological treatment plants. The final version of the ERAS Report is available at www.eraslazio.it. The residential cohort approach and the combination of environmental and health-related information proved invaluable in the assessment of the health impact of solid waste treatment in Lazio.