: Differences of Problem Solving Competences of OSN Mathematics Medal Winners by Sex. This study was carried out to explore whether different sexes influence the performances of OSN Mathematics Medal Winners . T wo subjects, namely MF ( female) and YB ( male), were selected and as signed to solve two mathematical problems. The subjects' p rofiles were obtained from in - depth inte rviews. The data indicate that there are differences in problem-solving profiles of the female and the male subjects, revealed in what they think and do when solving the mathematical problems and in the order of how they solve the problems. The order reflects the stages of Polya, and the differences observed seem to be caused by the different scheme of solving problems.