BACKGROUND: An integrated curriculum presupposes approximation of various disciplines into meaningful associations to focus upon broader areas. Team Based Learning (TBL) seems to be a suitable method for such approach. Our institution delivers almost all instruction in the first four years through active learning, mainly TBL. In two 20-week courses, during the first two semesters, covering Cell Biology, Molecular Biology, Biochemistry, Biophysics and Genetics, 10-16 TBLs were performed, and many challenges were faced when developing modules for the first year of a Medical School. AIM: Describe our experience in developing integrated TBL modules and how we approached these challenges. METHODS: Teaching plans, syllabus, pre-class and in-class materials from seven semesters (February 2016 to July 2019) were reviewed, and faculty was interviewed to provide understanding of challenges and how they overcame them. RESULTS: There were 5-7 TBL modules during first semester and 5-9, on the second. At each semester, at least one new TBL module was developed, totalizing 37 different modules. Development of objectives, content and appropriate application exercises integrating the different subjects, followed by lack of pre-class material in appropriate volume and difficult level were the main challenges. Literature search from the standpoint of disciplines in isolation to later find common ground, exploration of student’s early clinical experiences, clinical-research partnership and multidisciplinary discussion rounds provided clarification of objectives and ideas for exercises. Feedback from faculty from clinical years also ensured vertical integration between basic and clinical sciences. Creative pre-class videos and materials, using clippings and excerpts of different texts were developed. Reading guidelines are carefully prepared, often in the form of questions, to ensure that the student understands what goals to achieve when reading the material CONCLUSION: Developing TBL modules integrating 5 basic disciplines and clinical sciences in the first year of a medical school brought many challenges. Careful and creative preparation and team work were essential to overcome them.