This paper comprises two parts: a theoretical part in which a number of theoretical and methodological recommendations about research on absence are made on the basis of a review of selected literature, and an empirical part that contains analyses of absence from work in the Danish slaughterhouse industry. In the theoretical part it is asserted that sickness absence cannot be understood if it is viewed as a simple function of ill health or other individual factors, such as job dissatisfaction. Absence should rather be regarded as a coping behaviour that reflects an individual's perception of his/her health (illness) and is a function of a number of factors at different levels, primarily the combination of job demands and coping possibilities at the job (job strain). Several ideal methodological requirements regarding absence research are formulated on this basis. The empirical part presents an analysis of absence from work in the Danish slaughterhouse industry based on a study of 4407 slaughterhouse workers. It is shown that a number of factors at the company level, the job level and the individual level are associated with an individual's absence from work over a 12-month period. It is further shown that people with high job strain have a significantly higher absence rate, that there is a clear association between sickness absence and perceived health and that absence is part of a pattern along with other coping strategies which are directed against stressing working conditions and perceived ill health. Lastly, it is discussed whether absence from work is a functional coping strategy.