The case of a 30-year-old wood-worker, with rhinitis and asthma induced by exposure to the dust of Pau Marfim wood (Balfourodendron riedelianum) is reported. Hypersensitivity to this wood was confirmed by positive skin test, bronchial challenge test and RAST. The bronchial response was inhibited by sodium cromoglycate. Unexposed persons did not exhibit reactivity to this wood in any of the tests. When electrophoretic analysis of proteins in polyacrylamide gel was applied to a crude (phosphate-buffered) extract, an homogeneous distribution of low MW material was detected, with no clearly defined bands, suggesting the presence of filamentous type proteins. To the best of the author's knowledge, this is the first reported case of occupational rhinitis and asthma due to Pau Marfim wood dust. A type I (IgE-mediated) hypersensitivity mechanism was demonstrated but the non-glomerular nature of the proteins precluded further identification of the antigens involved.