Bronchial Asthma could be developed by occupational origin. 4-16% of bronchial asthmas are known to be related to occupational exposure. However, occupational asthma has not been reported from the periodic occupational health examination, but reported through case report from clinicians. The authors analysed hospital records to find out work-related bronchial asthma and their occupational characteristics at a university hospital in Jnchon. All records which were confirmed as bronchial asthma in adult by an allergist from June, 1996 to May, 1998 were selected. Through record reviewing, any suspected work related asthma was selected and the interview was done by phone or at the out-patient clinic. The possible cases were confirmed by additional tests including specific bronchial provocation test. Sixteen(3. 9%) out of 411 bronchial asthma were confirmed as work-related asthma. Eight cases out of 16 worked at furniture industry, three worked at dye manufacturing and two worked at musical instrument manufacturing industry. Others worked at farm and machinary industry. The confirmed asthmogen were toluene diisocyante(8), reactive dye(3), and grain dust(1). None of the cases was detected as work-related asthma in the periodic health examination. Twelve out of sixteen occupational asthma patients discontinued their work. The results suggested that many patients with occupational asthma were not reported and the periodic health examination was not an effective system for detecting the workrelated asthma. Thus, setting up the surveillance system involving allergist or pulmonologist would be important to detect and prevent occupational asthma.