In this study, the crystallization and preliminary X-ray analysis of a thermostable 1,3-1,4-beta-glucanase produced by Paecilomyces thermophila is described. The purified 1,3-1,4-beta-glucanase was crystallized using the hanging-drop vapour-diffusion method. The crystal belongs to the hexagonal space group P6(3)22, with unit-cell parameters a = b = 154.54, c = 87.62 A. X-ray diffraction data were collected to a resolution of 2.54 A and gave a data set with an overall R(merge) of 7.3% and a completeness of 94.6%. The Matthews coefficient (V(M)) and the solvent content are 2.38 A(3) Da(-1) and 48%, respectively.