The aim of this work was to determine the nature of the content that is often disseminated and the profile of a typical Portuguese firm which disseminates information on integrated management systems (IMS), environmental policy, corporate sustainability (CS), and corporate social responsibility (CSR) on its corporate website, towards sustainable development. The investigation consists of an exploratory analysis of 523 firms' websites that were certified by 2011, under the quality (ISO 9001), environment (ISO 14001), and occupational health and safety (OHSAS 18001) management systems. Four hundred twenty‐two firms from the overall population constitute a sample (n). The research method was based on the technique of content analysis, which allowed quantifying the contents of the information disclosed on the firm's website by category and subcategories of analysis. A holistic view on the size of the content available on the firm's website was determined using the index of information disclosure (IIDIMS/CS/CSR). As main findings, we can highlight management systems having been reported by 388 (91.9%) firms; quality management system, having been reported by 360 (85.3%) firms; environmental management system that contains environmental policy having been reported by 337 (79.9%) firms; and occupational health and safety management systems, which were disclosed by 332 (78.7%) firms. Another important finding is that disclosure of information on IMS/CS/CSR, on certified firms' website QEOHS, is more prominent when the dimension (size) of the firm is greater and when the legal form (structure) of the firm is a corporation.
In terms of theoretical assumptions to the contribution to the knowledge, it can be highlighted the mathematical foundation of the IID for IMS that was developed.