Public health surveillance and epidemiology are the foundations for disease prevention because they provide the factual basis from which agencies can set priorities, plan programs, and take actions to protect the public's health. Surveillance for noninfectious diseases associated with exposure to agents in the environment like lead and pesticides has been a function of state health departments for more than 3 decades, but many state programs do not have adequate funding or staff for this function. Following the efforts to identify core public health epidemiology functions in chronic diseases, injury, and occupational health and safety, a workgroup of public health environmental epidemiologists operating within the organizational structure of the Council of State and Territorial Epidemiologists has defined the essential core functions of noninfectious disease environmental epidemiology that should be present in every state health department and additional functions of a comprehensive program. These functions are described in terms of the "10 Essential Environmental Public Health Services" and their associated performance standards. Application of these consensus core and expanded functions should help state and large metropolitan health departments allocate resources and prioritize activities of their environmental epidemiologists, thus improving the delivery of environmental health services to the public.