This paper reports the effect of continuous summative assessment on the behaviour and learning environment of students. Assessing the performance of students is considered to be the most important thing a teacher can do for their students and it can have a profound effect on their learning. Continuous summative assessment was introduced as a form of assessment on a module within an undergraduate degree at a UK university. Student perceptions of the process were sought via a questionnaire and interviews. The paper describes the effect the assessment had on student motivation, their approach to learning and the change to their learning environment. The conclusion reached is that while continuous summative assessment may be time-consuming to administer, the rewards of an enhanced learning environment for students outweigh the additional burden on staff. The results should be of interest to those academics who are concerned with assessment and its impact on behaviour.