Chronic diseases are type of illnesses that require a continuous monitoring by physicians in order to keep the condition of the patient at the appropriate level. In this research a knowledge based system (KBS) is created and then integrated with the electronic health records database (EHR). This is used in order to create a system that is robust and able to predict the condition of any patient based on a certain number of factors that are usually defined by the health authorities. In order to create a model that able to predict a number of chronic diseases, then service oriented architecture (SOA) is used to accommodate these services. This present work deals with creating KBS that participate in the prediction process for diabetes patients.