Previously reported cases of botulism in infants have been diagnosed as infant botulism; that is, botulism caused by intestinal colonization by Clostridium botulinum with intraluminal production and absorption of toxin. Foodborne botulism is caused by ingestion of preformed toxin. We describe an unusual case of foodborne botulism in a 6-month-old infant caused by the ingestion of improperly prepared home-canned baby food. This represents the youngest age of onset for foodborne botulism in the United States of which we are aware and illustrates the need to rule out foodborne botulism, which represents a public health emergency, regardless of the patient's age. The diagnosis could have been readily missed or delayed in this case because the weakness was rapidly progressive rather than insidious, as is typical of infant botulism.