Science centers are one of the out-of-school learning environments in science education that have been increasing in numbers in recent years. Due to their importance for increasing both science-society communications and the quality of the education in schools, science centers are one of the focal points for the research conducted in out-of-school learning context. The study of science teaching in the field of science centers in Turkey is mostly confined to the schools or visitors' opinions about individual trips, yet; teachers' professional qualifications and needs related to teaching-learning in science centers are not sufficiently taken into account. This study is part of BILMER project supported by TUBITAK (Scientific and Technological Research Council of Turkey) 1001 program and it aims to determine the science and mathematics teachers' professional development needs and their experiences for learning in science centers. In this study, the data were collected with BILMER Teacher Questionnaire developed for the first time in Turkey. 355 science and mathematics field teachers working in 66 different provinces of Turkey, mainly in the provinces where science centers are located, participated in the questionnaire. According to the data obtained, teachers emphasize the high educational value of the activities organized in science centers; although they face various difficulties, they express that they do not receive enough education according to their professional qualifications. In addition, it has been determined that teachers need professional development on how to integrate activities in science centers, how to collaborate with science center explainers, and what kind of learning approaches can be used in science centers. These data were discussed in line with the relevant literature and suggestions were made for a professional development training to be given to teachers.