The aims of teaching environmental and occupational epidemiology to undergraduate medical students are numerous. An important contribution that epidemiology makes is the recognition that the health of the community is not determined only by the traditional clinical specialists of medicine. The need for epidemiologists, in the future, is likely to continue to increase with the increasing prominence of environmental and occupational epidemiology. It is due to the increasing contamination of the environment that causes the development of environment-related health problems. Professional epidemiologists devote all or the greater part of their time to the use of epidemiology in practice, teaching, and research. Health services administrators and other public health workers should have a thorough ground in the uses of epidemiological methods for tackling health problems in the community, including the evaluation of health services. Clinicians and graduates from other specialities should be able to recognise the role of epidemiology and biostatistics as they relate to their own work.