BACKGROUND: The terms "socioeconomic status", "socioeconomic position", "social classes" ... are widely used in epidemiology. They refer to various aspects of social position which is associated with many aspects of health. The position of individuals in the social hierarchy is multidimensional, i.e. defined by various socioeconomic factors. They can be individual (for example educational level, employment status, and occupation), household related (for example household income) or neighbourhood related (for example unemployment rate in the district of residence). These various factors can be associated with health at different periods during the life course, via a number of mechanisms, and they can possibly interact with one another. No socioeconomic indicator is better than the others or adequate in all study contexts. AIM AND METHODS: This paper presents a description of various socioeconomic indicators, and describes what they measure, and the advantages and limits of each of them. CONCLUSION: No indicator can be recommended in particular. Within the limit of available variables, the most relevant measurement depends on many elements, such as the study population and the aspect of health being investigated.