Over the past three or more decades, many studies have been written about teacher education and the preparation of science teachers. Presented here is one which investigated the effectiveness of scientific process skills on pre-service science teachers of Pamukkale University Primary Science Teacher Education Program for four years. This study uses a simple descriptive survey approach which is one-shot survey for the purpose of describing the effectiveness of a science teacher education program on scientific process skills of pre-service science teachers. The participants of the study consist of 186 primary science pre-service teachers in total from four different semesters of their teacher preparation program. Test of Integrated Process Skills II (TIPS II) was utilized to collect data. The data were analyzed using primarily multivariate statistical methods. One way ANOVA was used to identify patterns within cohorts regarding pre-service teachers' scientific process skills. Major findings indicated that Pamukkale University-Science Teacher Education Program helps to develop pre-service science teachers' scientific process skills effectively. Especially, science teacher education program affected pre-service science teachers' scientific process skills positively in the third and fourth grade.