The aim of this investigation was to study the factors that influence students to do mathematics in a level higher than the usual level arising from the usual syllabus. The sample was 339 students who participated at 25th National Mathematical Olympiad ``Archimedes'' in March 2008. They completed a questionnaire designed to measure the factors that influenced them to do mathematics. The results of this investigation show that the more important factors affecting students to do mathematics are: Mathematical competitions, their fathers, books, their school teachers, the publications of the Hellenic Mathematical Society and their mothers.