The purpose of this research was to study the relationships among mothers` sex role identity, role stereotypes and peer acceptance in preschoolers. The subjects were 136 children (4-6 years old) and their mothers in Pohang. The instruments used in this study were the Sex Stereotype Measure and Peer Nomination for children, and the Bem Sex Role Inventory for mothers. The data were analyzed using the One-way .NOVA, Pearson correlation, Cronbach`s a and Duncan`s test of multiple comparison. The findings of this research were as follows: 1) Boys` male-stereotyping was stronger than girls`. 2) Female-stereotyping was stronger in children who had an opposite-sex sibling, or, who were not, the first born child. 3) Although there appeared to be no effect of mothers` styles of sex role identity on children`s sex stereotypes and peer acceptance, mothers` high masculinity was correlated with boys` male-stereotyping and girls` female- and androgynious-stereotyping positively. 4) 6 year old children were accepted by same-sex friends better than 4 or 5 years olds, ;end boys with strong male-stereotyping evinced the tendency of accepting for same-sex friends only.