We examined mediational models of panic-fear, panic disorder (PD), and asthma outcomes among adult asthma patients. PD was assessed by the Anxiety Disorders Interview Schedule. Twenty-one asthma-PD patients and 27 asthma-only patients completed spirometry and questionnaires. Asthma-PD patients reported greater illness-specific and generalized panic-fear than asthma-only patients, despite no differences in asthma severity or physical symptoms during asthma attacks. Illness-specific panic-fear mediated the relationship between PD and poorer health-related quality of life, including emotional disturbance due to asthma. Illness-specific panic-fear was associated with more primary care office visits for asthma. Asthma-PD patients reported greater irritability during asthma attacks than asthma-only patients. Generalized panic-fear was directly associated with restriction of activities due to asthma and use of rescue medication for asthma. Neither measure of panic-fear was associated with asthma severity. Panic-fear experienced during asthma attacks may be an important area to target for improving health-related quality of life among asthma-PD patients.