OBJECTIVES: The Maternal and Child Health Epidemiology Program (MCHEP), jointly sponsored by the Centers for Disease Control and Prevention (CDC) and Health Resources and Services Administration (HRSA), was evaluated in 1996-1997. As part of this evaluation, an effort was undertaken to identify components of effective MCH epidemiology, to examine their prevalence across participating states, and to assess differences with respect to these components between MCHEP and non-MCHEP states. METHODS: A case-study evaluation was undertaken in which nine states (five MCHEP and four non-MCHEP) rated themselves on a benchmark questionnaire and participated in interviews conducted during site visits. At the completion of the evaluation, 16 components of effective MCH epidemiology in state health agencies were identified. The nine states were rated by the evaluation team on each component. Ratings across all states and between MCHEP and non-MCHEP states were compared. RESULTS: There was a great deal of variability among the nine states with respect to the presence of the components of effective MCH epidemiology. Components on which the states appeared weakest overall were the presence of adequately trained personnel, the presence of adequate management information systems to support MCH programs, and whether the state health agency's epidemiologic unit understands the MCH planning cycle. States with an MCHEP assignee had a higher overall mean score than non-MCHEP states across all components. There were seven components on which the two groups of states differed. These include whether the MCH director is empowered in the state health agency, whether the state health agency has identified internal epidemiologic capacity building as a priority, and whether analytic leadership is available for MCH epidemiologic activities. CONCLUSIONS: Building and maintaining MCH epidemiologic capacity in state health agencies requires attention to a variety of factors. While the presence of an MCH epidemiologist is important, this is only one of many components that must be considered as both the federal and state governments seek to promote and institutionalize effective MCH epidemiology in state health agencies.