Corporate environmental reporting makes good business and environmental sense. A big challenge for companies is to utilize the technical benefit of state of the art IT, especially of Internet-technologies and Internet-services. In this paper an approach of internet-based environmental reports by companies is presented. Three different levels are discussed: The first level deals with the basics of corporate environmental reports (CER) by companies. Illustrating the order within the emerging field of CERs a morphological box is suggested (section 1). Building on this, general requirements for corporate environmental reports are outlined (section 2). On the second level, the general reporting requirements are specified by IT-relevant challenges, seen as starting points for internet-based environmental reports (section 3). The immense technical benefit of using the Internet towards efficient, integrated, interactive, hypermedia-featured, dialog-oriented, and customised environmental reporting is analysed (section 4). On the basis of the technical benefit analysis, the state of the art of internet-based CERs is presented (section 5). The third level refers to the IT-application turning from the basics, IT-challenges and technical benefit to consequences for environmental reporting companies in practice. Thereby a fundamental framework for internet-based CERs is sketched (section 6). Grounded on this framework a basic architecture of an IT-implementation is explained (section 7).