The objective of this study was to analyze first-year UFRJ medical students' perceptions about the implementation of a blended learning (BL) experience in their Biochemistry I course. During the first semester of 2009, three Biochemistry professors used the Constructore course management system to develop virtual learning environments (VLEs) for complementing course Modules I, II, and IV, using different resources and activities. Forty-nine students (46%) took part in the study. Results show that, in general, students gave positive evaluations to their experiences with BL, indicating that the VLEs have not only motivated but also facilitated learning. Most of the students reported that access to resources in the three modules provided a more in-depth approach to Biochemistry education and greater study autonomy. Students suggested that the VLEs could be better used for promoting greater communication among participants. (Contains 2 tables.)