The American Crystallographic Association, Inc. is a non-profit, scientific organization of over 1,300 members in more than 35 countries.  ACA was founded in 1949 through a merger of the American Society for X-Ray and Electron Diffraction (ASXRED) and the Crystallographic Society of America (CSA). The objective of the ACA is to promote interactions among scientists who study the structure of matter at atomic (or near atomic) resolution. These interactions will advance experimental and computational aspects of crystallography and diffraction.  Understanding the nature of the forces that both control and result from the molecular and atomic arrangements in matter will help shed light on chemical interactions in nature and can therefore lead to cures for disease.


Membership in the ACA is open to any person who is actively interested in the purposes of the Association.  Student members are very welcome and their contributions to the life and vigor of the Association has always been important. There are 14 Scientific Interest Groups focusing on Best Practices for Data Analysis & Archiving, Biological Macromolecules, Cryo-EM, Fiber Diffraction, General Interest, Industrial, Materials Science, Neutron Scattering, Powder Diffraction, Service Crystallography, Small Angle Scattering, Small Molecules and Young Scientists.  Members may join as many of these as they wish. Each Scientific Interest Group is responsible for organizing sessions at National Meetings at least every other year.

Annual Meeting

The ACA holds its annual meeting each year in July, except every third year when they are held in May due to the IUCr Congress.

Mission Statement

The American Crystallographic Association (ACA) advances, promotes and preserves crystallography, structural science, and allied disciplines for the benefit of humankind.  The ACA provides students, young scientists and experienced crystallographers with opportunities to exhibit their achievements in research, creative and scholarly activities, and leadership. The ACA contributes to the intellectual, economic and scientific advancement of the communities and individuals it serves though conferences, publications and public outreach.

Vision Statement

The American Crystallographic Association (ACA) is committed to serving students and young scientists through education, and embraces its role as a leader and collaborative partner to meet the educational and research aspirations of structural scientists in North America and around the world. Our dynamic environment shapes the association to realize our shared future.  The ACA informs every dimension of its activities - cultivating learning, discovery of knowledge and encouraging shared leadership - to position the ACA as a model scientific interdisciplinary society.

Strategy Statement

The American Crystallographic Association (ACA) will actively respond to the needs and opportunities of structural scientists in North America by pursuing innovative partnerships, by adhering to our fundamental commitment to provide educational and research experiences to students and young scientists, and by supporting life-long learning and career development.

Constitution & Bylaws

The bylaws of the ACA are in the form of a Constitution established on November 1, 1970, with amendments and changes approved November 1992, July 1995, December 1999, December 2003.

Officers, Appointments & Office Staff

Officers include members of ACA Council: President, Vice President, Past President, Treasurer, Secretary and Canadian Representative.  Appointments include the Chief Executive Officer, Chief Financial Officer, and Director of Administrative Services.

Standing Committees

Standing Committees include the Continuing Education Committee, Data Standards & Computing and the Communications Committee.

Canadian Division

The Canadian Division exists to represent the interests of Canadian crystallographers within the ACA and to promote scientific discussion among the approximate 220 members resident in Canada.  The Canadian Division has their own Bylaws and Officers.   Find out more about the Canadian Division including history, meetings, jobs opportunities, facilities and more.

 Young Scientists




    2019 Meeting

 July 20 - 24

 Cincinnati/northern Kentucky