Previous studies have been inconclusive as to whether peak flow meter use teaches asthma patients to better perceive their own pulmonary functioning. This investigation utilized a delayed baseline design to determine if pulmonary awareness could be improved among a sample of 24 adult patients who compared daily peak expiratory flow rates (PEFR) with asthma symptom ratings. Results indicated that among this sample of adult patients: (i) perception of pulmonary functioning was poor, (ii) adherence to peak flow meter use was poor, and (iii) among patients who use peak flow meters daily, self-perception of pulmonary functioning did not improve significantly. Summary tables and descriptive statistics for pulmonary functioning are provided, and treatment implications are discussed.