The purpose of this study was to determine the abstract thinking levels of the science students attending the first and fourth year at two Palestinian Universities (Al-Aqsa and Al-Azhar). The sample consisted of 133 students from Science Education Departments (SE). The tool, used to measure abstract thinking, was one of the Science Reasoning Tasks developed by the CSMS in UK in 1994. The results showed that almost 65% of the 4th year science-education students was at levels capable of formal operational thought. However, only a very small minority showed capability of late formal operational thought (3.6%). About 30% of the 4th year students were at concrete thinking levels. In the first year, there were only 40% of the students who had formal thinking level and about 60% had concrete thinking level. The results showed a positive correlation between the scores of the students in the abstract thinking test with the achievement level in the universities (GPA). The results proved that there was a gap in the levels of abstract thinking, between the current thinking level and the expected one of the students. The students-teachers have not reached the minimum abstract level at which a science teacher should be, in order to teach high school science in the future. The results may be partially considered an evident of existence of unsuitable selection of students in SE Departments in the two universities. More data are needed in that regard. Generally, we may conclude that, the current systems in Science-Education Departments have not succeeded in assisting the students to reach their potential in terms of cognitive ability through four years of teachers preparation program. Some recommendations are included in the study.