One requirement for successful occupational health care is reliable information on occupational hazards. The aim of this study was to develop a simple, standardised method for workplace investigations for use in occupational health care. The theoretical framework of the method comprises the stress-strain model, the hazard-danger model, and risk behaviour theory. The new method, termed job load and hazard analysis, includes four stages: identification of hazards, their evaluation, conclusions and proposals, and follow up. Different methods are available for hazard identification. The identification starts with a rough analysis of five factors, chemical hazards, physical hazards, physical load, mental stress, and accident risk. Hazards and stress factors are assessed with an ordinal scale. Specialised methods are used if all hazards cannot otherwise be identified. The analytical procedure comprises: detection of hazards through observations and interviews at the workplace and with a questionnaire; assessment of findings as teamwork; and evaluation of the results of these assessments to yield conclusions and proposals made by occupational health care personnel. A data processing system has been developed for data storage and future use. The method has functioned in practice, improving the contents of the occupational health care programme and generating preventive measures. The method offers many new possibilities for controlling occupational hazards and studying relations between working conditions and workers' health.