The opportunistic yeast Malassezia sympodialis can act as an allergen and elicit specific IgE- and T-cell reactivity in patients with atopic eczema. The first identified major allergen from M. sympodialis, Mala s 1, is present on the cell surface of the yeast. Recombinant Mala s 1 was expressed in Escherichia coli, purified and refolded in a soluble form. Crystals of Mala s 1 were obtained in 25% PEG 8K, 0.2 M (NH4)2SO4. Crystals belong to space group P2(1)2(1)2, with unit-cell parameters a = 44.4, b = 163.7, c = 50.6 A, and diffract to 1.35 A resolution.