A chitinase has been isolated and purified from Crocus vernus corms. N-terminal amino-acid sequence analysis of the approximately 30 kDa protein showed 33% identity to narbonin, a seed protein from Vicia narbonensis L. The C. vernus chitinase was crystallized by the hanging-drop vapour-diffusion method using PEG 8000 as the main precipitant. The crystal belonged to the monoclinic space group C2, with unit-cell parameters a=172.3, b=37.1, c=126.4 Å, β=127° and two molecules per asymmetric unit. Diffraction data were collected to a resolution of 2.1 Å.