A cross-sectional study including 54 furniture factories and three control factories was conducted to survey lung function and prevalence of respiratory symptoms among woodworkers. Spirometry was performed on 2423 persons. Questionnaires regarding respiratory symptoms and wood dust exposure were completed by 2033 woodworkers and 474 controls. Personal passive dust measurements were performed on 1579 persons. The arithmetic mean +/- SD for equivalent inhalable dust was relatively low (1.19 +/- 0.86 mg/m3). Woodworkers had increased frequency of coughing with negative interaction between dust exposure and smoking. A dose-response relationship was seen between dust exposure and asthma symptoms, and a positive interaction for asthma was seen between female gender and dust exposure. Increased frequency of wheezing and a cross-shift decrease in forced expiratory volume in 1 second among workers using pinewood was seen. In conclusion, wood dust exposure might cause respiratory symptoms, despite a relatively low exposure level.