The purpose of this study is to examine the effects of negative life events on mental health and to explore possible main and moderating effects of spousal support on mental health with a focus on gender differences. The data for this study were taken from a nationwide random sample of 1,504 married men and women ranging in age from 30 to 59 through structured questionnaires. The data were analyzed using the SPSS WIN program which was used to calculate frequency, mean, 1-test, multiple regressions. The main results were as follows: First, by examining mental health of Korean men and women, women were more likely than men to experience higher levels of depression. Second, there was no gender difference in the sum of experience of negative life events, therefore the date of this study did not support the differential exposure hypothesis. In addition, men perceived more support from their spouses than women. Third, results show that especially the event concerning with job/financial problems has negative impacts on mental health of both men and women, and vulnerability to undesirable life events was not found. Fourth, spousal support is associated with better mental health regardless of gender, and it reduces the harmful effects of life events concerning with job/financial area for both men and women. Also, spousal support reduces the magnitude of the harmful effects of life events concerning with health of men. This study focused on the impact of negative life events and the couple process. It was possible to explore the strength of social support provided from spouse of most importance to the individuals. These results affirm the importance of supportive relationships between couples as a buffer, mitigating harmful effects of negative life events on mental health.