This paper describes a procedure for analyzing the gender gap in socioeconomic status between male-dominated professions and nonmale-dominated professions using the Japanese Panel Study of Employment Dynamics (JPSED). By using this data, differences were found in the distribution of educational background and employment status between men and women depending on the sex composition of the profession in which they are employed. Furthermore, the results of an examination of the differences between men and women working in male-dominated vs. nonmale-dominated professions showed that the relationships between occupation and education and between occupation and employment status differ between men and women. These results indicate the importance of analyzing differences within professions according to sex composition as well as analyzing the differences between men and women. Finally, the theoretical significance of this paper is described.