Background: Little is known about what primary care physicians know about children's physical growth and development and there are no consensus standards for knowledge and practice standards in this area. Objective: To promote the development of standards for assessing the growth and development of children by assessing primary care physicians' knowledge and practice patterns in comparison with the expectations of primary care educators and pediatric endocrinologists.Design: A mailed survey design with three stages: 1) assessment of Minnesota primary care physicians' knowledge and practices in childhood growth and development; 2) assessment of pediatric endocrinologists' and ratings of importance for primary care practice; and 3) assessment of primary care residency directors' ratings of how essential the same knowledge and practice areas are for primary care. Data were collected in 1997-1998. Participants: A total of 272 family physicians, 123 pediatricians, and 224 pediatric endocrinologists responded to a survey questionnaire mailed to family physicians and pediatricians in Minnesota, and U.S. members of a pediatric endocrine society. Main Outcome Measures: Primary care physicians' knowledge scores on a questionnaire on childhood growth and development, their self-reported practice patterns in this area, and the ratings of pediatric endocrinologists and primary care residency directors of the importance of these items for primary care. Results: The knowledge scores of both family physicians and pediatricians substantially exceeded the expectations of pediatric endocrinologists. Family practice residency directors and pediatric residency directors held similarly higher expectations for primary care physicians' knowledge. Pediatricians' knowledge met this standard, whereas family physicians' scores were significantly lower than expectations of their educators. There was general consistency of practice patterns between expectations and self-reported practice, except for weighing and plotting weights of children. Conclusions: Findings provide an empirical base for creating standards in primary care knowledge and practice for childhood growth and development.