Cephalosporins are well-known agents that may cause occupational asthma. There have been a few reports suggesting that its pathogenesis may be IgE-mediated. To the best of our knowledge, this is the first report of cefotiam-induced occupational asthma. A 36-year-old female, a nurse, visited our allergy department for the evaluation of occupational asthma. She had worked in the surgical inpatients’ ward and handled a few kinds of antibiotics for 4 years. At that time, she developed rhinorrhea, paroxysmal cough and chest tightness for 2 months. Her symptoms used to be aggravated during and shortly after her work and subsided several hours after work. However, her symptoms subsided spontaneously, because she was brought to the outpatients’ ward for recent 3 years. Therefore, she had only mild dyspnea on exercise. Methacholine bronchial challenge test revealed a negative response. The skin prick test with cefotiam (Fontaim(R)) showed a strong positive response and a specific bronchial provocation test with cefotiam demonstrated an early asthmatic response. A few days after bronchial provocation test with cefotiam, the methacholine bronchial challenge test showed a positive response. Further studies will be needed to evaluate the exact pathogenetic mechanism of cefotiam- induced occupational asthma.