After completing this article, readers should be able to: 1. Recognize the signs and symptoms that are suggestive of an inborn error of metabolism. 2. Describe the characteristics of different classes of metabolic syndromes. 3. Formulate a logical diagnostic approach to determining which specific condition is present when an inborn error of metabolism is suspected. 4. Delineate the value and scope of newborn screening programs. 5. Be aware of treatment modalities for inborn errors of metabolism.