This research aims to obtain information about the effect of instruction using scientific approach on the improvement of mathematical problem solving ability among students of State Junior High School (SMP Negeri) 13 Pontianak, West Kalimantan. The method used in this research was experiment research with a randomized pretest-posttest comparison group design. The results of data analysis showed that there were significant differences between the pretest and the posttest, namely using the scientific approach (pretest: 61.78%; posttest: 69.3 3%) and using CTL approach (pretest 58.50%; posttest 65.89%). This suggests that the improvement of the students\u27 ability in the mathematical problem solving using scientific approach is higher than the ability in the mathematical problem solving using contextual teaching and learning, and the improvement of the students\u27 ability is classified as moderate
