This study examined the reliability and validity of a new measure for evaluating symptoms in patients with chronic obstructive pulmonary disease (COPD): the Breathlessness, Cough and Sputum Scale (BCSS(R)). Designed as a daily diary, the BCSS is a patient-reported outcome measure that asks patients to rate the severity of the three symptoms, each on a 5-point scale: higher scores indicate more severe symptoms, Item scores are summed to yield a total score. Secondary analysis of data were from two multinational trials (n=629; 765). The BCSS item and total scores exhibited evidence of internal consistency (alpha = 0(.)70 daily; 0(.)95 to 0(.)99 over time) and reproducibility (ICC = 0(.)77 to 0(.)88), Correlations (r) with pulmonary function (FEV1 % predicted, PEF) were-0(.)01 (n.s.) to -0(.)36 (P < 0(.)001). Correlations with the St George's Respiratory Questionnaire total and SF-36 Physical Functioning subscale were 0(.)44 to 0(.)59 (P < 0(.)001). Breathlessness and total scores differentiated patients by disease severity (P < 0(.)01) and rescue medication use (P < 0(.)01). Cough, sputum, and total scores increased with sputum volume (r=0(.)27, 0(.)30, 0(.)31; P < 0(.)001), Patients for whom treatment was moderately or highly effective reported significant improvements in BCSS scores (P < 0(.)0001). Results suggest that the BCSS is a reliable, valid, and responsive patient-reported outcome measure of symptom severity in patients with COPD. (C) 2003 Elsevier Science Ltd.