The relationship between general health measured using the Sickness Impact Profile (SIP), lung spirometry, arterial oxygen saturation during exercise, and six-minute walking distance was studied in 141 patients with chronic airflow limitation. In addition the patients completed the Hospital Anxiety and Depression Questionnaire and the Medical Research Council (MRC) Bronchitis Questionnaire. Their mean age was 63 years (range 31 to 75) and their mean FEV1 was 47 +/- 23 (SD)% of predicted normal. The SIP scores were lower (i.e., the patients had better general health) than in previously reported patients who had greater physiological disturbance, but the profile of the different category scores within the SIP was similar to previous findings. Walking distance correlated with the SIP better than any spirometric measure or arterial saturation and accounted for 41% of the variance in SIP (p less than 0.001). The SIP score was considerably higher in patients who wheezed every day compared with those who did not (p less than 0.005). In patients who reported that their breathing was not normal between acute attacks of breathlessness and wheeze, the SIP score was twice as high as in those who felt normal between attacks (p less than 0.0006). Walking distance, depression score, and MRC dyspnea score correlated with SIP score independently of each other. A multiple regression incorporating these three variables accounted for 62% of the total variance in SIP score. Age, sex, and response to bronchodilator were not correlated with SIP score. We conclude that the SIP provides a valid measure of general health in a population of patients with chronic airflow limitation.