Participants (166 married couples, ages 20–85) were administered marital satisfaction and Pleasantness-Arousability-Dominance temperament scales. Participants with more pleasant and more dominant temperaments, and those who had mates with more pleasant temperaments, were happier in their marriages. Temperament accounted for substantially more variance (30%–34% in marital satisfaction than effect sizes reported in the personality/marital satisfaction literature. Because Pleasantness is a general index of psychological adjustment, findings implied that better adjusted persons, and those with better adjusted mates, were more satisfied in marriage. Unpleasant and submissive (i.e., depressed) wives were highly dissatisfied in marriage. Although intermate temperament similarity on Pleasantness and Dominance (but not on Arousability) correlated positively with marital satisfaction, similarity was a weaker and somewhat misleading predictor of satisfaction in comparison to findings when individual temperament scores were treated as separate variables. Also, weak results showed individuals selected mates with temperaments similar to their own.