PURPOSE: This study was done to investigate differences in maternal role confidence and parenting stress according to the infant's feeding method. METHOD: The participants were 257 mothers of infants aged 5~7 months. 145 breast-feeding mothers and 112 bottle-feeding mothers participated. The Maternal Role Confidence Scale and Parenting Stress Index(PSI) were used. RESULTS: The score of maternal role confidence of breast-feeding mothers (3.28) was significantly higher than that of bottle-feeding mothers(2.84). In addition, the parenting stress level of breast-feeding mothers(1.80) was lower than that of bottle-feeding mothers(2.97). However, the scores of maternal role confidence and the parenting stress level were not different according to the mother's and infant's personality characteristics. There was a significant negative correlation between the score of maternal role confidence and parenting stress levels(r=-.55, p<.001). CONCLUSION: Breast feeding mothers had more confidence of their maternal role, and a lower parenting stress level. Therefore, nurses must encourage infant mothers to breast feed since it is the best option for mothers as well as infants.