Purpose of this study was to determine the trend of changes in the mental health of married couples. Method was a descriptive-comparative study in which 230 married couples were selected from student's mass marriages in Tehran universities. From this sample, 213 couples in the first year of the study, 116 couples in the second year, 46 couples in the third year, 95 couples in the fourth year, 56 married couples in the fifth year, and finally 27 couples in the fourth year of their marriage completed the General Health Questionnaire(GHQ). Results indicated that except for the somatic symptoms subscale, differences between mean scores of other subscales as well as the total GHQ mean scores in different years were not significant. The best predictor of the GHQ total score in the fifth year of the study was the event of getting married itself. Also there weregender differences in terms of the GHQ scores, i.e. females have reported lower mental health in comparison with males. Discussion: The result showed a change may occur during first year of marriage is in relations and responsibilities of couples arid the expression of Jension in obtaining communication and conflictr resolution skills. Furthermore, this tension may be increased in women by occupational family and occur at ional roles during first years of marriage which impacts their mental health negatively.