The present paper deals with intellectual system for determination and evaluation of personalized patient's level of adherence. The most popular nowadays techniques for adherence evaluation are interview and questionnaires. We propose a new automated approach based on the comparison of direct patient's data with personalized treatment plan using fuzzy logic and standard ISO 13606. On the current step, we process only manually submitted data. For the next step we are going to introduce sensor devices for the purposes of personalized patients' adherence determination. The results can be useful for medical organizations with long-term patients.