On April 9, 1912, the law establishing the Children's Bureau was signed by President William Howard Taft. The original mission of the Children's Bureau was to "investigate and report … upon all matters pertaining to the welfare of children and child life among all classes of our people." This paper focuses on the transitional years from roughly 1950 to 1969, when the Children's Bureau's investigative mandate was transformed from a set of intramural activities that viewed maternal and child health research as part of a larger effort cutting across investigative, programmatic, and policy goals, and across different domains of the child's life, to an extramural research program focused specifically on maternal and child health. Discussion focuses on the mission of the Maternal and Child Health (MCH) Research Program, housed now within the Maternal and Child Health Bureau (MCHB), Health Resources and Services Administration (HRSA), of the U.S. Department of Health and Human Services.