The application of data mining techniques to health-related data is beneficial to medical research. However, the use of data mining or knowledge discovery in databases, and data matching and profiling techniques, raises ethical concerns relating to consent and undermines the confidentiality of medical data. Data mining and data matching requires active collaboration between the medical practitioner and the data miner. This article examines the ethical management of medical data including personal information and sensitive information in the healthcare sector. It offers some ethical and legal perspectives on privacy and the confidentiality of medical data. It examines the International landscape of health information privacy protection, relevant Australian legislation and recommendations to improve the ethical handling of medical data proposed by the Australian Law Reform Commission.