To estimate the occurrence of skin symptoms and the prevalence of contact allergy to occupational allergens, 84 male woodwork teachers were interviewed, clinically examined and patch tested. The tests included a supplemented European standard series and acetone extracts of wood dust of pine, spruce, juniper and birch. In addition, 10 colophony-allergic volunteers were tested with dilution series of wood dust extracts. Major colophony compounds in the dust extracts were analyzed with gas chromatography. We found a high 1-year period prevalence of generally mild hand eczema: 19%. Contact allergy was diagnosed to several allergens in the working environment, e.g., benzisothiazolin-3-one, nickel, formaldehyde and colophony. A clear relationship between patch test reactions to colophony and to coniferous woods, especially pine, was found. Exposure to wood dust at work caused dermatitis in a colophony-sensitized teacher.