ABSTRACT. In this study, we investigated the differences of mapping understanding and the types of mapping errors by the levels o f students’ cognitive/affective variables and the relationships between mapping understanding and these variables in learning ‘concentration and reaction rate’ with analogy. After administering the tests regarding logical thinking ability, visual imagery ability, analogical reasoning ability, self efficacy, and need for cognition as pretests, students learned with analogy. Then, students’ familiarit yand mapping understanding were examined. Analyses of the results revealed that the scores of the mapping understanding for the students with higher levels of all cognitive/affective variables except visual imagery ability and familiarity were significantly higher than those for the students with lower levels. The differences in the types of the mapping errors such as overmapping, failure to map, impossible mapping, artificial mapping, mismapping, rash mapping, and retention of a base feature were also found by the levels of students’ cognitive and affective variables. The scores of students’ mapping understanding were positively correlated with thos e of al lcognitive and affective variables. The results of multiple regression analysis indicated that students’ science achievement, logical thinking ability, and familiarity were significant predictors of mapping understanding. Educational implications of these findings are discussed.