Recent advances in genetic testing can help to provide a specific diagnosis to children born with syndromes that result in congenital anomalies and developmental delay. One such emerging condition is the 22q13 deletion syndrome. With the introduction of subtelomeric fluorescence-in-situ hybridization (FISH) analysis, the 22q13 deletion has become recognized as a relatively widespread and underdiagnosed cause of mental retardation. Primary-care physicians play an important role in the care of children with 22q13 deletion syndrome, from suspecting the diagnosis in a developmentally delayed child through the medical, developmental, and behavioral aspects of their care. Furthermore, they serve as a valuable source of support and advocacy for the family and a resource for other care providers. The remainder of this article addresses the current state of knowledge regarding 22q13 deletion syndrome and offers the primary-care physician a framework in which to provide care and information.