To assess current practice, perceived desirable practice and barriers related to the promotion of physical activity in general practice, a questionnaire was developed and distributed to all 1228 general practitioners in Perth. From these, 789 valid returns were received (71 per cent response). The mean age of the respondents was 45 years, 69 per cent were male, 52 per cent had postgraduate qualifications and 73 per cent were in full-time practice. General practitioners most frequently asked patients about their current level of physical activity and discussed physical activity programs when seeing patients with symptoms of conditions that could benefit from exercise, rather than asking all patients, new patients or patients previously seen. Walking specifically for fitness was the activity most likely to be recommended. General practitioners felt more able to offer general advice than specific advice on physical activity. Lack of time was reported most frequently as a barrier to the promotion of physical activity (47 per cent), followed by insufficient educational materials (29 per cent), and preference of patients for drug treatment (27 per cent). There were significant differences between self-reports of current practice and perceived desirable practice in the promotion of physical activity by general practitioners. Future strategies should aim to increase the frequency of advice to patients with specific health conditions.