This study investigated the role of each strategy in explaining sixth graders' (12-13 years old students') non-routine problem solving success and discriminating between successful and unsuccessful students. Twelve non-routine problems were given to 123 pupils. Answers were scored between 0 and 10. Bottom and top segments of 27% were then determined based on total scores. All scripts of pupils in these segments were then re-scored with regard to strategy use. Multiple regression analysis showed that strategies explain 65% of the problem solving success. Order of importance of strategies are as follows: "make a drawing," "look for a pattern," "guess and check," "make a systematic list," "simplify the problem," and "work backward." According to discriminant analysis results, strategies which play a significant role in distinguishing top and bottom students are "look for a pattern," "make a drawing," "simplify the problem," "guess and check" and "work backward," respectively.