The rising popularity of World Wide Web has brought portal solutions to a rapid development. More and more companies, agencies, departments have replaced or completed their Web sites with a portal, gaining advantage from the consequent integration of information, services and applications. On the other hand, mobile technologies are really catching on, and the next generation Internet must face the problem of providing information to heterogeneous handheld devices. In this paper, we want to define an approach to design contents for multi-device portals, based on the transcoding and adaptation of an HTML source to a mobile markup language. Although our approach doesn't target a specific class of devices, the transcoding functionalities have been tested for WAP phones, I-Mode terminals and PDAs. We have developed a set of tools that can help designers to follow our approach, from the definition to the validation of the portal contents. KEYWORDS Mobile Access; Portals; HTML/WML Conve...