BACKGROUND: The dominance behavioral system (DBS) is a biologically based system that underpins individual differences in motivation for dominance and power. However, little is known about the DBS in childhood. In order to make strong claims about the DBSs trait-like properties and predictive validity, a clearer understanding of its early development is required. PARTICIPANTS AND PROCEDURE: In a pilot study aimed at developing a behavioral coding system for dominance, a key facet of the DBS, we collected and coded observational data from 58 children, assessed at ages 3 and 5-6. These data were examined in conjunction with measures of child temperament via observational measures, and symptoms of psychopathology. RESULTS: Dominance was moderately stable in early childhood to a degree comparable to other early child temperament traits. Consistent with the study hypotheses, boys were more dominant than girls, and dominance was negatively associated with childrens behavioral inhibition, effortful control, and internalizing symptoms. CONCLUSIONS: These results provide initial support for the validity and developmental sensitivity of an objective coding system for assessing facets of the DBS in early childhood. Ultimately, the use of this coding system will facilitate future studies of how early DBS predicts psychological adjustment later in life.