The potential of market research data for secondary analyses lays mainly in the fields of consumer behaviour, consumption patterns and media usage. Their availability for empirical social and economic research depends on the professional rules as well as on the readiness of the market research agencies and their clients to make them available. Many market research projects are focused on specific target groups. This focuses their potential for secondary analyses on representative insights regarding these groups as well as on basic and methodological research. In most cases it is necessary that public availability of market research data is agreed contractually with the client of the research project. For a number of market research projects access to the official statistical data is important for methodological reasons. Therefore private research agencies should have the same privileged access to them as academic research institutions. As long as this access has not been established it is unlikely that their readiness to make market research data publicly available will increase.