Children referred to child welfare have higher-than-average rates of physical, mental, and developmental health conditions, yet coordinating medical care to address their complex needs is challenging. This study investigates complex health characteristics of child welfare-involved children to inform evolving patient-centered medical homes that incorporate multidisciplinary care and social health determinants. Study questions include: (1) To what degree do child welfare-involved children present with complex physical, behavioral, and developmental conditions? (2) How does the clustering of complex health concerns vary according to developmental stage? (3) What demographic factors relate to complex health concerns? Data are from 5873 children (birth to 18) who participated in the National Survey of Child and Adolescent Well-being II.