Over the past two decades, science has become established as a core school subject in schools in England and Wales, taken by all students aged 5 to 16. But increasingly questions have been raised about the suitability for many students of the curriculum they are required to follow (Murray and Reiss, 2005). From September 2006, schools in England and Wales will begin teaching a new science curriculum to 14-16 year-olds, leading to the General Certificate of School Education (GCSE) qualification. This article describes the background to the science curriculum changes, the pilot Twenty First Century Science, and assesses the likely impact of the changes on students moving to study science at a higher level. (Contains 5 tables and 3 figures.)