In order to determine the compliance of Canadian physicians with evidence-based hypertension guidelines, a self-administered questionnaire survey was distributed to a stratified random sample of 473 physicians in Central Alberta, Canada in December 1995. Excluding non-deliverable questionnaires, a response rate of 67% was obtained. Twenty-five per cent of respondents routinely used the fourth Korotkoff sound to define diastolic blood pressure (DBP). Investigations recommended for the initial workup of a patient with mild hypertension included serum creatinine (90%), electrolytes (72%), glucose (50%), cholesterol (44%), electrocardiogram (65%), and urinalysis (76%). The non-pharmacologic treatment advice routinely advocated for patients with mild hypertension included salt restriction (87%), weight loss (100%), and regular aerobic exercise (92%). While 46% of respondents recommended antihypertensive therapy for an otherwise healthy patient with an average DBP of 95 mm Hg, 76% recommended therapy for patients with the same BP plus target organ damage or other cardiovascular risk factors. Medication choices varied, although angiotensin-converting enzyme inhibitors were chosen by 46% for patients with uncomplicated essential hypertension and 67% for patients with other cardiovascular risk factors, and beta-blockers were the most frequently chosen first-line agents (56%) for the patient with target organ damage. There was considerable variability in the self-reported practice patterns, and concordance was greater for those recommendations which were consistent across the currently available guidelines. Consistent with the principle underlying all of the current hypertension guidelines, respondents were more aggressive in their treatment of hypertensive patients with other cardiovascular risk factors or target organ damage.