In spite of the recent publication of various guidelines for the treatment of chronic bronchitis and chronic obstructive pulmonary disease (COPD), no studies have investigated whether or not they are being implemented by caregivers. Our aim was to determine what treatment protocols for patients with chronic bronchitis and COPD are most commonly applied by general practitioners in Spain and to identify factors associated with the prescription of certain drugs. A standardized questionnaire was administered to 268 general practitioners working in the 17 autonomous communities of Spain. The stratified sample of respondents was selected to reflect the population of each community. Valid information on 2,414 patients was collected. Men accounted for 74% of the patients. Mean age was 67 years (SD = 10). Lung function data were available for 1,130 (47%) and mean FEV1 was 1,523 ml (56% of the theoretical reference value). Patients without lung function data in spite of having signs of severe symptoms had suffered more acute exacerbations and generated more visits to the emergency room and to their primary care doctors in the preceding year than had patients who had undergone lung function testing (p < 0.03; p < 0.001; p < 0.003, respectively). The treatments most often prescribed were short-acting inhaled beta-2 agonists (56%), inhaled corticoids (47%), theophylline-containing drugs (43%), and long-lasting beta-2 agonists (41%). Patients who had not undergone function tests received more mucolytics (47% versus 27%, p < 0.001) and fewer anticholinergics (20% versus 35%, p < 0.001). The factor most highly associated with prescription of all drugs was severity of disease measured by dyspnea. Treatment protocols for chronic bronchitis and COPD in general practice in many aspects show differences from current guidelines. Noteworthy is the extensive use of inhaled corticoid therapy and long-lasting beta-2 adrenergic agonists and the infrequent prescription of anticholinergics. The lack of lung function data is associated with poor pharmacologic management of disease and higher rates of morbidity.