The CFRS behavioral pediatrics research program investigates questions at the interface of child development and physical health. Two major areas of this research program are described here. Research in the first area, Child Development and Early Health Care Experiences, includes studies of children's knowledge, implementation, and evaluation of strategies for coping with stressful medical experiences; the development of children's understanding of health and health care; and relations among children's health histories, pediatric health care utilization, and maternal health beliefs. Development under Cocaine Exposure comprises the second major area of research; these studies address issues central to understanding ongoing transactions between biological factors and environmental conditions as they relate to diverse developmental outcomes.