The goal of this study is to provide information on the formation of ego-identities of adolescents and practical knowledge for making reasonable career decisions by analyzing the correlation of ego-identity and career maturity of high school students. This study was conducted with 316 high school students with the result being that males had a higher sense of ego-identity than females, and 12th graders marked higher than 10th graders, with a significant difference seen between the groups (p<.01). For career development, females ranked higher than males with again, 12th graders marking the highest out of all the grades. A positive relation was seen between the ego-identity areas (independence, self-receptiveness, future assurance, goal oriented, initiative, and closeness) and career maturity; with the sub-categories of career maturity each having an effect on the students’ ego-identities. The result of the study indicates that the ego-identity sub-category that affects career development the most is self-receptiveness. Through related research of ego-identity and career development conducted throughout elementary school, middle school, and high Received(June 27, 2014), Review request(June 28, 2014), Review Result(1st: July 11, 2014) Accepted(December 10, 2014) Publish(December 31, 2014) 560-759 Dept. of Education, Jeonju University, 303, Chonjam-ro, Wansan-gu, Chonbuk, Korea email : kuk4@jj.ac.kr (Corresponding Author) 561-756 The Graduate school of education, Jeonbuk National University, Korea email : impmola@hanmail.net A Study on the Relationship between the Ego-Identity and Career Maturity of High School Students Copyright c 2014 SERSC 236 school, it is required for the school education system to put in effort in providing career guidance.