Two studies were conducted in an attempt to replicate an earlier finding of self-esteem deficits in adolescent girls with early onset of insulin-dependent diabetes mellitus (IDDM). Participants in Study 1 were 139 adolescents with IDDM who completed the Perceived Competence Scale for Children (Harter, 1979). A 2 (gender) X 2 (group: age of IDDM onset: early vs. late) multivariate analysis of variance (MANOVA) did not reveal a significant interaction effect. Study 2 included 136 adolescents (104 adolescents with IDDM and 32 physically healthy adolescents) who completed the Self-Perception Profile for Children (Harter, 1985). A 2 (gender) X 3 (early IDDM onset, late IDDM onset, physically healthy control) MANCOVA, controlling for the effects of social class and adolescent age, also indicated no significant interaction effect. Thus, we found no differences in self-esteem based on age at disease onset and gender in two independent samples of youths with IDDM. In Study 2, significant gender and group effects were revealed, but when these findings are compared with normative data and data from our physically healthy sample, the results suggest that the youths with IDDM were functioning within the normal range on self-esteem. The importance of these findings in regard to the deficit versus adaptation models of chronic illness is discussed.