As a part of AssistMe system, the reporting system has been developed for the thoracic surgery domain. Reporting System is defined as software for dynamic report generation purpose and based on the data-mining techniques. The target users of the future reporting system-physicians, administrative staff, and patients-have been identified. Two major types of clinical reports have been found: predefined and customized. The decision of splitting reports into groups has been taken mainly because users were heterogeneous and had different access rights to the sensitive information. Data-mining process in the reporting system is based on descriptive statistics. It allows dynamically mined AssistMe databases and generates statistical reports about patient's morbidity, mortality, and comorbidity. Information is visualized in the chart way and can be also observed in tabular form. User interaction is also supported by the system.