Attentional biases have been observed in populations with psychological disorders, but have been under-investigated in populations with physical illnesses. This study investigated potential attentional biases in asthma as a function of mood. Asthma (N = 45), and healthy (N = 39) participants were randomly allocated to a depressed or a neutral mood state induction. They completed a visual probe task that measured participants' reaction times to health-threat and neutral pictures and words. Compared to the healthy controls, the asthma group showed attentional bias towards health-threat pictures in depressed mood, and avoidance of health-threat pictures in neutral mood. Attentional biases were found in a group with a physical illness as a function of induced mood. It is suggested that attentional processes in people with physical illness may be important in relation to symptom perception and illness management.