The screening of workers for health problems has been ubiquitous in the worksite for many years. These screening procedures may have ethical and policy implications. Three common types of screening in use include pre-employment, early identification of health problems, and employee monitoring. Pre-employment screening may be used to screen out individuals who would be at increased risk for health problems if exposed to hazardous materials at the worksite. Screening for disease may discriminate against individuals with particular ethnic and racial backgrounds, since some diseases may be concentrated in a particular ethnic group. Society may be facing an important dilemma between strategies to improve or maintain the health of employees and access to jobs and socioeconomic position, especially when biological markers for disease susceptibility which have nothing to do with worksite exposure are used. There are few restrictions on the uses of pre-employment screening information provided by an employee to an employer, while at the same time the validity of the tests used in pre-employment screening may be questioned. Biological screening tests should not be used as a part of employee selection, unless the screening test indicates sensitivity to hazardous substances at the worksite. For risk reduction screening at the worksite, ethical considerations include degree of voluntariness, potentials for misuse of information, problems of confidentiality, and the importance of providing services to support risk reduction. Risk screening also raises the problem of defining who the patient is when the screening results indicate a strong genetic component. On the positive side, however, these screening tests have the potential to reduce the level of illness and disability in society. Clinical and educational interventions can be targeted on individuals rather than groups at high risk. (ABL)