This study was conducted to examine pre-service science teachers' critical thinking dispositions and problem solving skills based on gender, grade level and graduated high school variables. Also relationship between pre-service science teachers' critical thinking dispositions and problem solving skills was examined based on gender, grade level and graduated high school variables in this research. Sample of this study consists of 124 students studying in Science Education Department of Adnan Menderes University Education Faculty in city of Aydin in Turkey. As data collection tools, "California critical thinking disposition inventory and problem solving inventory" were used. T-test, one way variance analysis (ANOVA) and multi regression analysis were used to analyse data. According to the findings of this study, pre-service science teachers' critical thinking disposition levels differ significantly based on gender and graduated high school while no significant difference was found between pre-service teachers' critical thinking disposition levels and grade levels. Another finding indicate no significant difference in pre-service teachers' problem solving skills based on gender and grade level, but a significant difference was found in problem solving skills based on graduated high school type. According to regression analysis results, no significant relationship were found between pre-service science teachers' critical thinking dispositions and problem solving skills based on gender and grade level variables. On the other hand, a significant difference was found in pre-service science teachers' critical thinking dispositions and problem solving skills based on graduated high school type. (Contains 7 tables.)