Since a patient record is typically a document updated by many users, required to be represented in many different layouts, and transfered from place to place, it is a good candidate to be represented structured and coded using the SGML document standard. The use of the SGML requires that the structure of the document is defined in advance by a Document Type Definition (DTD) and the document follows it. This paper represents a method which derives an SGML DTD by starting from the description of the usage of the patient record in medical care and nursing.