Detailed knowledge of the molecular properties of fungal allergens is a prerequisite for improvements in diagnosis and therapy of allergies caused by molds. Cladosporium herbarum, Alternaria alternata and Aspergillus fumigatus are among the most prevalent causes of mold allergies. Moreover, these species occur worldwide. Compared to allergens from pollens, insects and foodstuffs, little is known presently about the most important allergens of C. herbarum and A. alternata. One reason for this might be the low quality of commercial mold extracts used for allergy testing [1]. The major allergens of A. alternata [1, 2]and C. herbarum (unpubl. observations) are secreted proteins that are recognized by about 80 and 60% of the patients sensitized to the given mold species. However, we have previously shown that several other allergens of the molds are cytoplasmic household enzymes and proteins [3]. Prominent among them is enolase, a glycolytic enzyme that is the second most important allergen in terms of frequency of sensitization to both C. herbarum and A. alternata.