Visual short-term memory (VSTM) research suggests that the adult capacity is limited to three or four multifeature object representations. Despite evidence supporting a developmental increase in capacity, it remains unclear what the unit of capacity is in children. The current study employed the change detection paradigm to investigate both the capacity and nature of the representations of VSTM in 7-year-olds, 10-year-olds, and adults. Two experimental conditions were used to compare memory performance for single-feature objects with that for multifeature objects. Results provided further and more convincing evidence for a developmental increase in VSTM. Furthermore, the ''loading up'' of features in the multifeature condition was found to incur no significant performance deficit in all age groups. These findings are explained in terms of a developmental increase in the number of integrated multifeature object representations in VSTM. (Contains 1 table and 1 figure.)