1H-3-Hydroxy-4-oxoquinaldine 2,4-dioxygenase (HOD) is a cofactor-devoid dioxygenase that is involved in the anthranilate pathway of quinaldine degradation. HOD has been proposed to belong to the α/β-hydrolase-fold superfamily of enzymes. N-terminally His6-tagged HOD has been crystallized by the hanging-drop vapour-diffusion method using sodium/potassium tartrate as a precipitant and CuCl2 as an additive. The structure was solved by the single anomalous dispersion (SAD) technique using data collected to 3.5 Å resolution at the Cu absorption peak wavelength. The crystals belong to the primitive tetragonal space group P43212, with unit-cell parameters a = b = 153.788, c = 120.872 Å.