Inositol dehydrogenase (IDH) is an enzyme that catalyses the NAD + -dependent oxidation of myo-inositol to scyllo-inosose. The enzyme has been purified to homogeneity by means of Ni 2+ -affinity chromatography and was crystallized in both native and selenomethionine (SeMet) labelled forms using the microbatch method. SAD X-ray diffraction data were collected to 2.0 Å resolution from a SeMet-labelled crystal at the Advanced Photon Source (APS) and a MAD data set was collected to 1.75 Å resolution at the Canadian Light Source (CLS); this is the first reported anomalous diffraction experiment from the CLS. The crystals belong to space group I222 and contain one molecule per asymmetric unit.