Remembering object identities requires binding visual features together in working memory to form integrated object representations. Research with adults suggests that such feature binding is achieved through space: features at a given spatial location are bound to create integrated objects that are anchored to a spatial map of the object layout. Critically, 4-year-old children do not form such spatial maps, whereas 5-year-old children do. This suggests that 4-year-olds might have difficulty binding features together in visual working memory. We tested 4- and 5-year-old children and adults in a change detection task, and found that 4-year-olds showed a binding-specific deficit. Thus, the ability to represent integrated objects in visual working memory is a relatively late developmental achievement. We suggest that before 5 years of age childrens object representations are primarily mediated through visual long-term memory.