OBJECTIVES (i) To document variation in management of hypertension in pregnancy; (ii) to determine whether this variation falls within current management guidelines; and (iii) to make recommendations for developing future guidelines. DESIGN Questionnaire-based survey. SETTING Australia and New Zealand. POPULATION All specialist obstetricians. METHODS Questionnaires were sent to 1198 obstetricians in Australia and New Zealand. Those returned by respondents currently in obstetric practice were analysed. Information was obtained on their current clinical practices relating to the diagnosis and management of hypertension in pregnancy. RESULTS Of 1198 obstetricians surveyed, 973 (81%) replied. Of these, 686 (71%) were responsible for obstetric care. Considerable variation in practice was found, particularly in relation to the measurement of blood pressure, the determination of hypertension and significant proteinuria, and the decision to institute antihypertensive drug treatment. The recommendations of the Australasian 1993 Consensus Statement appeared to have had little influence on practice. There has been a striking increase in the use of magnesium sulphate for the prevention of convulsions in preeclampsia. CONCLUSIONS There is significant variation in management of hypertensive pregnancies that differs from current guidelines. It is not known whether this diversity adversely affects clinical outcomes. Until further outcome evidence is available, consensus statements may be better confined to basic aspects of management for which there is high level evidence.