Recent research has raised questions regarding the consistency of unrealistic optimism and related self-enhancing tendencies, both within cultures and across cultures. The current study tested whether the method used to assess unrealistic optimism influenced cross-cultural patterns in the United States and Japan. The results showed that the direct method (a single comparison judgment between self and peers) produced similar patterns across cultures because of cognitive biases (e.g., egocentrism); specifically, participants were unrealistically optimistic about experiencing infrequent/negative events but pessimistic about experiencing frequent/ negative events. However, the indirect method (separate self- and peer judgments) produced different patterns across cultures because culturally specific motivational biases emerged using this method; specifically, the U.S. sample was more unrealistically optimistic than the Japanese sample. The authors discuss how these results might influence the interpretation of previous findings on culture and self-enhancement.