In order to describe the attitudes towards the treatment of extremely preterm infants, a questionnaire presenting a series of fictitious situations concerning imminent extremely preterm labour and treatment of an infant born after 24 weeks gestation was mailed to all physicians employed at obstetrical or paediatric departments in Denmark. The questionnaire was designed in two versions, differing as regards the parents' situation and attitude towards treatment. Each version was sent to half of the sample. Of 954 questionnaires 664 (69.6%) were completed and returned. Most respondents advocated active treatment prior to and immediately upon delivery, but many would withhold more intensive treatments or withdraw treatments in case of severe complications. The parents' situation and attitude towards treatment played a role in forming the decision choice to a significant proportion of the respondents. In severe cases, many would provide morphine in doses that could unintentionally hasten death, while few were in favour of legalizing active euthanasia.