In 2003, a new prospective payment system will be introduced in Germany, which is based on the Australian Refined Diagnosis related Groups (AR-DRGs). Physicians must code diagnoses and procedures themselves. Inaccurately or incompletely coded patient records can result in considerable underpayment, so enhancing physicians' coding compliance and competence seems crucial. Coding shall be well integrated in the electronic patient record, providing a simple interface with background information, which is invoked out of the clinical documentation. This paper describes an existing implementation and possible further development.