Workers exposed to a variety of wood dusts are known to experience work-related respiratory symp- toms, including occupational asthma. There are, however, few reports of occupational asthma due to spruce wood. We present the case of a 31-year-old sawmill owner with severe asthma caused by exposure to spruce wood dust, who developed asthmatic symptoms after 2 years of working. Investigations included clinical examination, routine laboratory tests, spirometry, chest X-ray, total serum immunoglobulin E (IgE) and specific serum IgEs against various woods and other occupa- tional allergens. Additionally, we monitored the peak expiratory flow rate (PEFR) and symptom score both at work and when off work. Specific serum IgE for spruce wood was detected (7.8 IU/ml). The results of PEFR and workplace symptom-score monitoring, coupled with an elevated eosinophil count in induced sputum, supported the diagnosis of occupational asthma. To our knowledge, this is the first well-documented case of occupational asthma induced by spruce wood dust. A type I im- munological mechanism seems to be responsible.