Objective To compare Year 1 medical students' perceptions of their educational environment at the end of Year 1, with their expectations at the beginning of the year using the Dundee Ready Education Environment Measure (DREEM). Methods Year 1 students (n = 130) at the University of East Anglia Medical School were asked to complete the DREEM during their induction week at the beginning of Year 1, thinking about the educational environment they expected to encounter (Expected DREEM), and again as part of a compulsory evaluation at the end of Year 1, thinking about the educational environment they had actually experienced (Actual DREEM). A total of 87 students (66.92% of the starting cohort) completed the DREEM on both occasions and gave permission for their data to be published. Results The Expected DREEM score was 153 out of a maximum of 200, and the Actual DREEM score was 143. Student's expected perceptions of learning and teachers, and their expected academic self- and social self-perceptions were all more positive than their actual perceptions. There was no difference between expected and actual perceptions of atmosphere. Specific aspects of the educational environment showing dissonance were identified. In some areas students' low expectations had been matched by their actual experience. Conclusions Medical students had started Year 1 with expectations about the educational environment that had not been met. However, areas showing dissonance received low item scores on the Actual DREEM and as such would be picked up for remediation, even without information about student expectations.