This research aimed to analyze the influence of Problem Based Learning model towards the learning outcomes in Mathematics subject of fifth grade students of Sekolah Dasar Negeri 30 Pontianak Selatan. The method used in this study was Quasi Experiment Design research using nonequivalent control group design. The samples are 20 fifth grade students in Class VA. The results of the data analysis showed average obtained post-test in the experiment class was at 78,5 while the control class was 66. The results of the effect size data calculation from the both experimental and control classes were 0.79, which was classified medium; it means that the application of the Problem Based Learning model influenced the learning outcomes of students in the Mathematics subject of fifth grade students of Sekolah Dasar Negeri 30 Pontianak Selatan