The purpose of this research is to enhance pre-service teachers' problem-solving skills by giving them opportunity to understand the problem solving process. The study, using an experimental approach, was conducted with 85 pre-service elementary school teachers. The experimental group experienced problem based learning (PBL), while the control group experienced traditional instruction (TI) in their science instruction course. Independent t-test and content analysis were used to analyse the quantitative and qualitative data. The quantitative results, supported by the qualitative research, revealed that the problem solving skills of the pre-service elementary school teachers experiencing PBL were increased more than those experiencing TI. (Contains 4 tables.)