A computer implemented system and method for matching drugs and diseases involves matching drugs identified in a specific patient's prescription claim records with diseases identified in the patient's medical claims. A weighted relationship is generated between the matched drugs and diseases by calculating a link weight in accordance with a preprogrammed formula for each of the diagnosis codes identified in the patient's medical claims that is identified as associated with the disease identified and the drug. The link weight provides a statistical match association value to each of the matched diseases identified by way of a diagnosis code in the patient's medical claim and the drug identified in the prescription claim.