Piaget's and Kohlberg's interview and scoring methods for assessing moral judgment in children were empirically compared. Based on cognitive development and social learning theories, six hypotheses were tested on 139 elementary school children. After being interviewed, the children participated in a moral conduct task. Multiple linear regressions and analyses of variance were computed using the variables of age, sex, rationale, Piaget interview score, Kohlberg interview score, and moral conduct score. The Piaget and Kohlberg interviews correlated only 46% with each other. Results indicate that: (1) moral judgment increases with age; (2) moral conduct increases with age; (3) boys obtain higher moral judgment scores than do girls - - confirmed by Kohlberg's but not by Piaget's method; (4) girls conform to rules better than do boys; (5) moral judgment and moral conduct are positively related - - confirmed by Kohlberg but not by Piaget scores; and (6) provision of a rationale does not necessarily result in a higher positive relationship between moral judgment and moral conduct. Results support the cognitive developmental position, but may reflect differences in the instruments used, children's limited ability to use words and memory spans, and sex differences in social learning. A follow-up study was conducted. (Author/JLL)