The ASPH Education Committee led the development of a core competency model for the Masters in Public Health (MPH) degree in the five, core curricular public health areas: biostatistics; environmental health; epidemiology; health policy and management; and social and behavioral sciences. ASPH developed the competencies in response to the challenges of 21st century practice; the proliferation of competency-based training in public health; increased emphasis on accountability in higher education; competency recommendations by national organizations; ongoing changes in practice; increasing incorporation of competencies into accreditation criteria; and the development of a voluntary credentialing exam for public health graduates. The first iteration of the model, Version 1.3, released in January 2006, is intended to apply to MPH students in schools and programs in public health upon graduation, regardless of the students' area of specialization or intended career trajectory. The five workgroups focusing on the core areas in Version 1.3 of the model used modified nominal group processes to identify and further specify 48 sub-competencies that emerged in "Phase 1" of the framework. Development and refinement of additional competencies not directly linked to the core MPH curriculum continued in "Phase 2." Workgroups in "Phase 2" worked to refine competencies in public health biology as well as specify competencies in six cross-cutting areas -- communication; diversity and cultural proficiency; leadership; professionalism and ethics; program planning and assessment; and systems thinking. These latter competencies will be incorporated with the discipline-specific competencies in a comprehensive competency framework for MPH degree candidates by the fall of 2006.