The purpose of this study was to investigate the relationships of self-differentiation with conflict tactics behavior and marital adjustment among married men and women. Specifically, this study tried to examine the differences in the levels of conflict tactics behavior and of marital adjustment according to the levels of self-differentiation. The participants of the present study were 332 married men and 355 women who lived in Chonlabuk-Do province. The major results of this research were as follows. First, there was no significant difference in the level of total self-differentiation between men and women. There were significant differences in the degrees of sexually coercive conflict tactics behavior and marital adjustment between sexes. Second, results of difference analyses showed that there were significant differences in the levels of conflict tactics behaviors and of marital adjustment according to levels of self-differentiation. Finally, in the case of married men and women, the variable significantly affecting the conflict tactics behavior and the marital adjustment was the levels of self-differentiation. Based on the results as above, this research discussed the issue of the concept of self differentiation applied to Korean situation, and suggested some implications for family life education for decreasing conflict between spouses and for enhancing marital relationship.