This study was planned to investigate the patterns and the effect of science journal writing on the science process skill and the scientific attitude of elementary school students. This study tried to show their perceptions about science journal writing in order to find out the value of science journal writing. For this purpose, one class of 6th graders in an elementary school was tested. The results from this research show as follows: Science journals are classified into 9 types according to content and form. Writings about curiosity are the most frequent. Science concepts are found in observational journal. Science journals are more effective in the development of the science process skills and scientific attitude. Students are revealed to be in positive aspects through the research about science journal. In conclusion, science journal writing should be emphasized in science education for elementary school students.