OBJECTIVES: To establish national baseline information on asthma management practices of physicians, to compare the reported practices with the Canadian Consensus recommendations and to identify results potentially useful for interventions that improve physician asthma management practices.DESIGN: National, stratified cross-sectional survey.SETTINGS: The 10 provinces and two territories of Canada, from 1996 to 1997.PARTICIPANTS: Questionnaires were sent to 4489 physicians stratified by province/territory and specialty group (family/general practice, respirology, internal medicine, pediatrics and allergy/immunology); 2605 responses were received.OUTCOME MEASURES: Methods for the diagnosis, treatment, education and follow-up of patients with asthma ('asthma management practices').RESULTS: Significant variations existed among the five specialty groups in asthma management practices. A low use of objective measures of airflow limitation to assist with diagnosis was found among some respondents (mostly family physicians). Up to 40% of physicians regarded the daily fixed dosing (three or four times a day) of inhaled, short acting beta2-agonist as 'first-line therapy' for moderate to severe asthma. A minority of physicians reported using written action plans for patients or referring them to other health professionals for asthma education. Insufficient time during appointments and a perceived lack of appropriate educational materials were frequently cited as reasons for not providing asthma education. The perceived knowledge of the Canadian Consensus recommendations varied among physicians but was lowest among nonspecialists.CONCLUSIONS: The survey showed variations in certain aspects of the management of asthma by physicians. The findings will help to target specific areas for future physician education programs and other behavioural change strategies.