The implications of adoption for the emotional and behavioral adjustment of children have been an issue in child welfare for many years. Past research has suggested that adopted children are over-represented in mental health settings. In addition, some studies have suggested that adopted and nonadopted children differ on measures of social, emotional, behavioral, and cognitive functioning. The current study used data from a large, representative sample in the United States to examine whether adopted children are more likely to have had mental health contacts or emotional or behavioral problems than nonadopted children. Age of placement in the adoptive home was examined as a variable contributing to the adjustment of adopted children. Results suggest that adopted and foster children are more likely to have mental health contacts than nonadopted children. Results are mixed regarding whether adopted and foster children have more behavior problems than nonadopted children. However, significant differences between adopted, foster, and nonadopted children disappeared when a small group of influential cases were removed. This suggests that the differences seen between the groups reflect a small number of cases and are not representative of the groups of adoptees and foster children as a whole. The vast majority of adopted children showed patterns of behavior problems similar to those of nonadopted children. These results are discussed in relation to the past literature and areas for future research.