In the current research, the authors examined children's observed compliance in a family clean-up paradigm and parents' reports of coparenting to predict young children's conscience (e.g., affective discomfort and moral regulation) in a sample of 58 families with two parents and at least two children. The authors found relations between parents' reports of children's conscience development and observer-rated compliance in a family clean-up session, and significant correlations between coparenting and conscience development. There were a greater number of significant results for younger, 2-year-old siblings than for older siblings, which may reflect the importance of the period between 2 and 3 years for the emergence of conscience. Multiple regressions revealed that younger siblings' age, observed compliance/noncompliance, and parents' reports of coparenting were all significant in predicting parents' reports of affective discomfort and moral regulation. Findings underscore the importance of continuing research on whole-family dynamics when studying young children's early conscience and moral regulation. (Contains 2 tables and 1 note.)