The gestational age and birth weight cut off for intact survival in extremely preterm infants is unclear. There is uncertainty among obstetricians and neonatologists about when it is inadvisable to institute intensive care. The suggested definition in relation to viability is when mortality does not exceed 50% but the corresponding figure for disability is undetermined. On foot of these concerns many groups have produced consensus statements on viability over the past 15 years. In this paper we examine the findings in 7 consensus statements on viability- British Association of Perinatal Medicine, American Academy of Pediatrics, The Fetus and Newborn Committee Canada, The Dutch Group, The Australian Group, Nuffield Institute of Bioethics, Neonatal Section of the Irish Faculty of Paediatrics. A number of points of agreement emerge. All would provide intensive care at 26 weeks and most would not at 23 weeks. The grey area is 24 and 25 weeks gestation. This group of infants constitute 2 per 1000 births. The difficulty is that there are a number of confounding variables. Girls have approximately 1 week advantage over boys, every day increases survival by 3%, the benefits of a full course of antenatal steroids, the problem of multiple birth, the baby's condition at delivery. Also concerns have been expressed about basing policy on short-term follow-up only. Extreme prematurity is both uncommon and complex and should be managed in high volume tertiary centres that are familiar with the necessary facets for decision making.