D-Arabinose isomerase catalyzes the isomerization of D-arabinose to D-ribulose. Bacillus pallidus D-arabinose isomerase has broad substrate specificity and can catalyze the isomerization of D-arabinose, L-fucose, L-xylose, L-galactose and D-altrose. Recombinant B. pallidus D-arabinose isomerase was overexpressed, purified and crystallized. A crystal of the enzyme was obtained by the sitting-drop method at room temperature and belonged to the orthorhombic space group P2(1)2(1)2, with unit-cell parameters a = 144.9, b = 127.9, c = 109.5 A. Diffraction data were collected to 2.3 A resolution.