A [beta]-1,3-glucanase from the thermophilic fungus Chaetomium thermophilum was overexpressed in Pichia pastoris, purified and crystallized in the presence of 1.8 M sodium/potassium phosphate pH 6.8 as a precipitant. Data to 2.0 A resolution were collected in-house at 293 K from a single crystal. The crystal was found to belong to space group P21, with unit-cell parameters a = 64.1, b = 85.8, c = 68.5 A, [beta] = 93.1degrees and one molecule in the asymmetric unit.