The purpose of this research is to examine the impact of activities based on scientific process skills on problem-solving skills of 4th grade students in science lessons. In the study a non-equivalent control group pre-test and post-test design type of quasi-experimental method was used. The research study group was composed of 30 students with 15 each in the experimental study group and control group. In the experimental and control groups, for scientific process skills, the “Scientific Process Skills Test (SPS)”,and for problem-solving skills, the “Problem Solving Inventory for Children at Elementary Education Level (PSIC)” were used as pre-test and post-tests. Activities including scientific process skills in the experimental group were applied for 8 weeks and 16 lesson hours, while no intervention was made to the control group. In the data analysis process, the Mann-Whitney U test and Wilcoxon Signed-Rank test were used. According to the data obtained from the research, it was observed that there was a significant difference in the post-test scores in the Scientific Process Skills Test (SPST) and the Problem-Solving Inventory for Children (PSIC) of the students in the experimental group compared to the students in the control group. According to these findings, it can be stated that activities including scientific process skills develop problem-solving skills of students in primary science education.