To date, researchers have frequently investigated students' attitudes toward courses supported by problem-based learning. There are several studies with different results in the literature. It is necessary to combine and interpret the findings of these studies through a meta-analysis method. This method aims to combine different results of similar and independent studies through statistical techniques. Research findings of 47 studies that meet the criteria for meta-analysis are included in the meta-analysis of the study to determine the effects of problem-based learning on students' attitudes as compared to traditional teaching. Also, some mediator variables are as follows: the status of a study, application time, education levels, scientific field of application, and sample size. As a result of the analysis, it has been found that problem-based learning has a low positive effect on students' attitudes. It means that problem-based learning is effective in helping students gain a positive attitude toward courses.