The structure of nickel dimethylglyoxime has been determined. The compound is orthorhombic with lattice constants, ao = 16,68 A, b o = 10.44 A, and co = 6.50 A. The space group for the structure is D262h - Ibam;The atomic positions were determined by three dimensional Fourier methods. The structure factors used in computing the electron density function were obtained from visually estimated intensities on Weissenberg and precession photographs. Back-shift corrections have been applied, and the errors in the final parameters have been determined;The nickel dimethylglyoxime molecule is planar. Although the molecular symmetry required by the space group is C2h , the symmetry may be as high as D2h . A layer structure exists in the crystal with a layer spacing of 3.25 A. An interlocking of molecules between layers and within the layers occurs in the crystal resulting in tightly packed structure. The close packing is suggested as a possible explanation for the insolubility of nickel dimethylglyoxime;The observed O-H-O distance of 2.44 A suggests the existence of an unusually strong hydrogen bond in the structure. An attempt is made to correlate the structure results with the infrared absorption spectra of the compound.