To assess awareness and understanding of obstructive airway diseases by primary-care physicians, the authors surveyed a randomly selected population of 75 primary care practitioners. During one-on-one interviews, physicians were presented with a standardized case scenario and a subsequent series of open-ended questions concerning asthma and COPD. Each respondent was presented in randomized fashion with one of two versions of a case description of a hypothetical 52-year-old male smoker with a recent upper respiratory tract infection and persistent productive cough. The only difference between case descriptions was that one included explicit reference to an earlier tentative diagnosis of chronic bronchitis (CB version); the other description made no specific mention of this diagnostic term (NCB version). Chest radiographs were requested by 80 percent of physicians and sputum cultures by 50 percent, these percentages not differing significantly between CB and NCB groups. Spirometry was requested less often than either of the foregoing tests (21 percent). The CB group requested spirometry significantly more often than the NCB group (38 percent vs 5 percent, p < 0.05). The most frequently mentioned primary diagnosis was bronchitis/pneumonia (33 percent), followed by bronchitis (28 percent) and chronic bronchitis (16 percent), all of which were similar in both groups. However, the diagnostic term "COPD" was the primary diagnosis in 16 percent of the CB group, compared with 8 percent in the NCB group (p > 0.05). Oral antibiotics were the most frequently chosen first-line drug therapy (63 percent). In subsequent questions concerning the management of obstructive airway diseases, primary practitioners distinguished COPD from asthma conceptually, but their prescribed therapy for the two disorders was less distinct. beta 2-agonists were selected most frequently and similarly as initial therapy for both disorders (53 percent). Minor differences between first-line therapeutic choices included nonsignificant trends toward the more frequent mention of anticholinergic bronchodilators for COPD than for asthma (10 percent vs 0 percent) and the more frequent selection of inhaled corticosteroids for asthma (12 percent vs 5 percent). The authors conclude that to the extent that questionnaire responses reflect actual practice, primary care practitioners (1) have a low index of suspicion for obstructive airway disease, (2) markedly underutilized spirometry as a screening tool, (3) consider beta 2-agonists first-line therapy for COPD and asthma, and (4) despite considering COPD and asthma different disease processes, choose similar medications for each disorder.