The purpose of the current study employing the survey method is to determine the pre-service science teachers' perceptions of the principles of scientific research and to investigate the effects of gender, grade level and the state of following scientific publications on their perceptions. The sampling of the current research is comprised of 125 pre-service science teachers attending the Department of Science Teaching in Mugla Sitki Koçman University in the spring term of 2014-2015 academic year. As the data collection instruments, Information Form to elicit the demographic characteristics of the pre-service teachers and five-point Likert type "Scale of Scientific Research Principles" developed by Campell, Abd-Hamid and Chapman in 2010 and adapted to Turkish by Tatar, Feyzioglu, Buldur and Aydogdu (2014) were employed. Frequencies and percentages were calculated for their perceptions of the principles of scientific research, t-test was run to test whether the pre-service teachers' perceptions vary significantly depending on gender and grade level variables and one-way variance analysis was used to test whether their perceptions vary significantly depending on their state of following scientific publications. At the end of the study, it was found that the pre-service teachers' perception levels of the principles of scientific research are high, their perceptions of the principles of scientific research vary significantly depending on gender variable in favor of male participants; however, their grade level and state of following scientific publications do not have significant effect on their perceptions.