Ligninolytic basidiomycetes were screened for their ability to reduce aryl acids to the corresponding aldehydes and alcohols. Seven fungal strains converted p-anisic acid in high molar yields to the reduced products. The white-rot fungus Bjerkandera sp. strain BOS55 was one of the best reducing strains and was highly tolerant towards high concentrations of different aromatic acids. It was tested for the reduction of p-anisic, veratric, 3-chloro-4-methoxybenzoic, 3,5-dichloro-4-methoxybenzoic, 3,4-dichlorobenzoic, 4-fluorobenzoic, and 3-nitrobenzoic acids. All of these compounds were reduced to their corresponding aldehydes and alcohols.