Objective This study was planned to determine the Medical Biochemistry Laboratory Summer Internship how perceived by the students of the medical faculty and its contribution to the level of practical and theoretical knowledge of the clinical biochemistry laboratory. Materials and methods Participating of the Medical Biochemistry Laboratory Summer Internship, Sakarya University Faculty of Medicine term 1(D-I) and term 2(D-II) students were pre-tested at the beginning of the internship and post-test at the end of the internship.A questionnaire form consisting of 26 questions was used in the study. Changes of general and personal knowledge levels were determined in pretest and posttest by creating individual code for all the students, Results The pre-test and ppost test mean scores of D-I and D-II students were 60±24.1, 70.3±24.6, and 68±23.6, 78.8±25.2 respectively. Posttest scores were significantly higher than the pretest sco- res(p=0,009) in all groups.When students were separated by terms , the pre-test and post-test scores of D-II students were significantly higher than the D-I students. Conclusion Higher post-test scores than the pre-test scores show that, internship education increases the knowledge of students. In addition to their lectures, elective summer internships would be beneficial for their active learning. So they can easily understand that, how does clinical laboratory work. This type of active learning programmes also be efficient in their medical life and would be a guide to the speciality choice in future.