One of the backgrounds changing of the curriculum 2013 was in response to the low literacy of Indonesian children according to PISA and TIMSS test results. To overcome this problem, the government adopted a policy of implementing a scientific approach in schools. The purpose of this study was to explore the obstacles faced by science teachers in applying scientific approaches in schools. Data collection techniques using questionnaires, observations, and focus group discussion. The results of the research showed that (1) Lesson study can improve teacher's pedagogical competence in applying scientific approaches,(2) The main obstacle of teachers was the lack of time in carrying out the process of scientific approach in learning, especially at the stage of conducting experiments,(3) Lack of time preparation for national and entrance examinations to higher schools. It was concluded that although lesson study was effective in increasing the ability of teachers to apply scientific approaches, but they are reluctant to apply it because they were afraid of running out of time in conducting the experiment and achieving their national final exam material targets when a scientific approach was applied.