Coughing is the most common symptom in people attending primary health care. Because the prevalence of asthma and chronic obstructive pulmonary disease (COPD) is not well known, the aim of this study was to establish the prevalence of unknown asthma and COPD in people consulting for a persistent or recurrent cough in primary health care in Sweden. Seventy-two adult patients were recruited consecutively at an acute consultation with a medical history of a persistent or recurrent cough. A medical history and a physical examination were performed according to a standardized form. Four patients (6%) fulfilled the criteria for asthma and five (7%) for COPD. The prevalence of asthma in this sample was less than that in western countries generally. These findings highlight the importance of people, especially women and smokers, with persistent or recurrent cough being carefully and promptly assessed with standardized measures including spirometry and repeated peak expiratory flow measurements. This knowledge should he conveyed to the general public as well as to primary health professionals.