As the number of non-native speakers of English studying at universities in the United Kingdom (UK) has grown, so has the need to provide pre-sessional English for Academic Purposes (EAP) courses. One of the challenges facing the organisers of such courses is deciding how to determine whether students have completed them successfully and whether they are ready to enter their academic departments. This paper reviews research into assessment on pre-sessional and other EAP support courses, and summarises the results of a survey of practice in a number of universities in the UK and other countries. It describes how assessment on pre-sessional courses has evolved at one British institution (Lancaster University), and outlines some of the problems that have led to changes in recent years. Explanations will be given of the methods used to pilot and refine a new assessment procedure and of the attempts that have been made to investigate its validity.