THE INFANT who is hospitalized for failure to thrive, and in whom, after extensive investigation, no pathologic diagnosis can be made, is a familiar phenomenon in pediatric practice.1-6The sequence of diagnostic procedures frequently involves a protracted hospital stay. This interval also permits observation of emotional and motor development as well as parent-child interaction. The infant usually improves in the hospital setting, but may not. If the studies yield no evidence of organic disease, emotional or nutritional deprivation may be suspected. Appropriate psychosocial remediation is initiated, and the patient is discharged to be followed as an outpatient. It is the purpose of this communication to point out that these babies may be at risk of serious injury or violent death within the ensuing months. The three cases reported were admitted to the Kaiser Foundation Hospital in San Francisco. Report of Cases Case1.—A 13-month girl weighing 5,104 gm (11