The characteristics of childhood as a unique developmental stage of life, the continuity of child health with adult health, and a distinctive child health care system justify a separate focus of health services research on children. Child health services research (CHSR) currently lacks the tools necessary to monitor the impact of health system change on children's health and health care and to compare the effectiveness of alternative treatment modalities. There is an urgent need to build the research capacity of this field of inquiry. Ignoring or minimizing attention to CHSR is both shortsighted and ultimately costly for families and the entire nation. We present arguments for why children merit a separate focus in health services research, identify factors that have led to the failure of appropriate development of CHSR, and offer a set of strategies for how to build the research capacity of the field.