The evolution of medical education started since ancient times. It depended on a master-student relationship. The master was a perfect expert concerned with learning and interested to his trainers and followers. In the early 1900s Abraham Flexner, an American higher education expert, suggested that medical schools must be linked to universities, should have a based curriculum and strong educational programs including fluently basic medical sciences and all stages of medical education should be given in classes, laboratories and hospitals.  WHO recommended integration of topics in medical education to overcome the redundancy of knowledge and to enhance student ability on problem-solving, clinical skills, and critical thinking and deal more with preventive medicine and health of the society. Problem-based learning (PBL) is a common method in medical schools around the world. Many educators suggested that a PBL curriculum had to be strengthened by a limited number of well-chosen lectures. Unfortunately traditional lectures are still the most popular instructional method in the universities. Educational innovation and reform new methods of integrated teaching challenged teachers to change how they plan curriculum and make clinical teaching relevant to the lessons taught using these newer methods. The balance of clinical and basic medical sciences and their integration in a manner that best serves the medical student are sure to be the focus of expected innovations in medical education.