The purpose of this work is to develop a web based decision support system, based on fuzzy logic, to assess the motor state of Parkinson patients on their performance in onscreen motor tests in a test battery on a hand computer. A set of well defined rules, based on an expert’s knowledge, were made to diagnose the current state of the patient. At the end of a period, an overall score is calculated which represents the overall state of the patient during the period. Acceptability of the rules is based on the absolute difference between patient’s own assessment of his condition and the diagnosed state. Any inconsistency can be tracked by highlighted as an alert in the system. Graphical presentation of data aims at enhanced analysis of patient’s state and performance monitoring by the clinic staff. In general, the system is beneficial for the clinic staff, patients, project managers and researchers.