Traditionally, a ketogenic diet is given to drug-resistant children with epilepsy to improve seizure control. Inducing a ketogenic state in patients with cancer may be a useful adjunct to cancer treatment by affecting tumor glucose metabolism and growth while maintaining the patient's nutritional status. A ketogenic diet consisting of 60% medium-chain triglyceride (MCT) oil, 20% protein, 10% carbohydrate, and 10% other dietary fats was provided to a select group of pediatric patients with advanced-stage cancer to test the effects of dietary-induced ketosis on tumor glucose metabolism. Issues of tolerance and compliance for patients consuming an oral diet (consisting of normal table foods and daily MCT oil "shakes") and for patients receiving an enteral formula are reviewed. Preliminary use of the MCT oil-based diet suggests a potential in pediatric patients with cancer.