Purpose: Over the last few decades, corporate social responsibility (CSR) has received a large amount of attention in research and in practice. As a response to the growing awareness of and concern about social and environmental issues, an increasing number of companies are proactively publishing their CSR-related principles and activities. The overall research question of this study is derived from legitimacy theory and is aimed at elucidating the relationship between industry sector and CSR communication. The paper aims to discuss these issues. Design/methodology/approach: The empirical examination encompasses a sample that includes the annual reports of all German DAX-30 companies from 1998 to 2009. First, based on a content analysis, categories of CSR-related communication are defined. Second, these categories are used in a quantitative analysis with a longitudinal perspective to evaluate the hypothesis that companies in controversial industries communicate their CSR more intensely than companies in non-controversial industries. Findings: The qualitative study leads to a category system that accounts not only for CSR-related activities but also for CSR philosophies and motives as the normative basis of CSR communication. The quantitative results support the hypothesis that companies in controversial industries are more active in CSR communication than companies in non-controversial industries. Originality/value: Existing studies analysing CSR communication activity have been largely inconsistent and often use unsystematic approaches in choosing industries for comparison. Therefore, in this study, to overcome some of these deficiencies, a combination of quantitative and qualitative approaches addresses the concept of controversial industries. © Emerald Group Publishing Limited.