Objective: To estimate associations among peer education, social support and self esteem and their influences on performance of breast self-examination (BSE). Method: Seven volunteer peer educators were given the BSE training programme and in turn educated 65 women students in the university. BSE knowledge evaluation forms developed by Maurer were applied for evaluation. Other data were collected with questionnaries for the Coopersmith Self-Esteem Inventory and Scale of Perceived Social Support over three months. Results: Knowledge level points of students and the BSE practice ratio were increased by peer support. There was a positive relationship between average BSE knowledge points and social support and self-esteem. Conclusion: The results showed positive relationships among BSE knowledge, social support and self esteem, these affecting the BSE performance level.