The forms of the medical records are different from one institute to another. Moreover, medical records are always stored in free text. Consequently, medical records almost can not be logically analyzed and understood by machines. In this paper, we have applied the information retrieval (IR) technique in the using of medical records. We have implemented an IR system for the users, such as doctors and patients, to query similar or related medical records to support diagnosis and treatment. Knowledge retrieval for reuse is the key idea of this system.