The aim of this study is to determine the effects of Problem Solving method on achievement, retention and students' attitudes toward the lessons in the unit of "History of Turkey" in the course of Social Science at the 6th grade of elementary school. This research possessing the pre and post test model design has been carried out in Kültür Elementary school in the city center of Bolu District with the participation of 73 elementary school students as the informations of the experimental and the control groups. The unit of "History of Turkey" was covered in the experimental group according to the principles of problem solving method whereas in the control group the same unit was covered with traditional teaching methods that are more teacher-centered and are usually delivered through lecturing with one way communication. There was a significant difference between the experimental group, in which the course was administered in the problem solving method, and the control group, in which the course was administered in the traditional learning method, with respect to the cumulative total of pre-test and post-test scores and their scores of achievement, retention and attitude in favor of the experimental group in the course on Social Science.