Two types of bias in the attribution process are the responsibility bias, in which individuals tend to assume more than their objective share of responsibility, and unrealistic optimism, in which individuals tend to assume that future outcomes will be positive. In order to investigate these self-serving biases among married and divorced individuals, and to show their association with the attribution of conflict in close relationships, 73 men and 86 women (97 married, 4 separated, 58 divorced) completed a mailed Marital Attitudes questionnaire. Results showed that, as predicted, individuals perceived themselves as both better than average and as more responsible for their partners' marital problems. The two forms of bias operated independently. The optimism bias was lower among divorced individuals and those with a higher level of conflict. The responsibility bias was unrelated to respondents' marital status or marital conflict. The findings suggest that there are at least two different types of self-serving bias in the attribution process of close relationships. Future research should address the relationship between the two. (LLL)