The Commission on Neutron Diffraction was established at the 7th General Assembly in Moscow, in 1966. The proposal at that time is given below.

The Commission on Neutron Diffraction shall be concerned with those aspects of crystallography which can be studied almost uniquely by using neutron beams.

The name was changed to Commission on Neutron Scattering by the General Assembly at the Beijing meeting in 1993. The Commission requested the change in name because it wished to represent and serve all neutron scatterers who consider that they use crystallographic techniques.

The Commission on Mathematical and Theoretical Crystallography (MaThCryst) has a dedicated website at www.crystallography.fr/mathcryst/.

The IUCr-MaThCryst commission was started on September 2002 as an informal workgroup from a nucleus of researchers who felt the necessity of trying to reverse the current trend towards "crystallography as a black-box tool". 

The Commission on Magnetic Structures (CMS) operates a dedicated website at magcryst.org.

The Commission on Journals comprises the Co-editorial boards of the journal publications of the IUCr, Acta Crystallographica Section A, Acta Crystallographica Section B, Acta Crystallographica Section C, Acta Crystallographica Section D, Acta Crystallographica Section E,

The main activity of the Commission on International Tables is the planning, editing and maintaining of the volumes of International Tables for Crystallography, which are published both in print and online by the International Union of Crystallography.

The website for the Commission on Inorganic and Mineral Structures (CIMS) is at www.crystallography.fr/cims/.

 IUCr-CIMS was founded to promote and achieve the following aims:

At the 14th Congress in Perth, in 1987, a High-Pressure Group was established within the Commission on Crystallographic Apparatus to represent and support high-pressure crystallography. The subsequent decade saw an extraordinary growth in the range and quality of high-pressure diffraction studies – particularly using powder methods – on both synchrotron and neutron sources. This was stimulated by the power of present-day sources, and by major developments in detectors and high-pressure technology.

Electron crystallography is the branch of science that uses electron scattering and imaging to study the structure of matter.

This new Commission on Diffraction Microstructure Imaging was established at the Prague General Assembly in August 2021.

The Commission on Crystallography of Materials was established ad interim by the Executive Committee at its meeting in Boston 2012 and confirmed at the Hyderabad General Assembly in August 2017. This Commission was given ad interim status as recommended by the Executive Committee and voted upon at the General Assembly in Melbourne, Australia in August 2023. This Commission was subsequently formed in December 2023.