Rheumatic fever (RF) is an important cause of illness and premature death in New Zealand with particularly high rates in Maori and Pacific children. This research aims to identify important risk factors for this disease. It will use a case-control study to compare cases of RF (150) with controls who do not have the disease. Cases and controls will be interviewed about such factors as housing conditions, crowding, tobacco smoke exposure, treatment of sore throats, skin infections, and oral health. Throat swabs will be tested for the streptococcus bacteria that cause RF. Blood specimens will be collected for vitamin D, iron stores, and other factors. At the end of the study, researchers expect to identify risk factors for RF, particularly those that are modifiable. This information will be used to guide prevention programmes to help lower rates of RF in New Zealand and internationally.