Heart disease is a major cause of ill-health and death in adults. The risk factors for heart disease, if present in children, carry over into adult life. Childhood obesity has reached epidemic proportions in Canada and is associated with many heart disease risk factors such as high blood pressure. Another complication of obesity is obstructive sleep apnea. Sleep apnea is marked by snoring at night, pauses in breathing and low oxygen levels and occurs in up to 60% of obese children, but it is diagnosed in less than 20% of obese children. Importantly, sleep apnea in children, like obesity, is linked with high blood pressure and heart disease. Thus, children with sleep apnea who are obese are likely to have an increased risk for high blood pressure and heart disease. Currently, there is little knowledge of the extent of heart disease in obese children with sleep apnea.