The recent introduction of the Dundee Ready Education Environment Measure (DREEM) has fulfilled a long-felt need for a test instrument specifically meant to evaluate health professions education institutions. It was intended in this study to ascertain the overall DREEM score for the newly established Faculty of Medical Sciences of University of Sri Jayewardenepura (FMS/USJ), Sri Lanka and to compare the DREEM score of the students in the pre-, para- and clinical phases of the traditional curriculum practiced in this school. A total of 339 students belonging to the pre- (n = 147), para- (n = 116) and clinical (n = 76) phases of the medical course participated in this study. The DREEM questionnaire was administered face-to-face after one of their routine lectures to each group of students. The age of the students ranged from 20 to 28 years and the gender distribution was almost equal. The overall DREEM score was 108 (54%) for the pooled data for all three phases. There was no significant difference on the overall DREEM score obtained by each phase of students. The overall DREEM scores of pooled data and also for each domain indicated that the position of the FMS/USJ qualifies to be placed just on the third grade (one below the best) within the overall DREEM scale. However, on analysis of the responses for each domain, Students' Perception of Teachers (SPT), Students' Academic Self-Perceptions (SAP) and Students' Social Self-Perceptions (SSP) showed significant difference between the pre-, para- and clinical phases. Similarly, 22 out of the 50 items showed significant differences between the pre- and clinical phases. Overall, the DREEM demonstrated compatibility of its scores along with the gradual development that took place at this medical school over the last 10 years. Thus, the DREEM could be utilized in a variety of situations.