We introduce an approach that allows the use of mobile devices as an extension to an already existing HIS providing the full range of functions of the system. GSD has developed an extension to its product IS-H*MED (SAP R/3 based) using mobile devices, WirelessLAN and Web technology, which allows synchronised access to IS-H*MED functions and data likewise. The most important functions provided by the application are synchronised worklists, the presentation of service requests and findings, case histories and patient information as well as bed scheduling. Added features include SMS and access to the clinic Intranet. The substantial advantages of our approach lies in the rapid and simple feasibility to user-specific and practice-orientated solutions for handhelds using established technology like HTML and scripting. Extensions to and adaptation of an existing application are easy to realise by adding and linking further HTML-pages.