Using an object relations perspective, the representations of birth and adopted mothers in a sample of 52 nonreferred adoptees were studid. To better understand the specific effects of adoption on the construction of 2 maternal representations, birth and adoptive maternal representation of adopted children was compared with that of nonadopted children. In addition, the effect of incongruous representations of birth and adoptive mothers on adoptees’ externalizing and internalizing behaviors was explored. Compared with nonadopted children, adoptees’ representations of the mothers appear as more concrete and less benign. Among adopted children, representations of the birth mothers were found to contain split negative aspects of the adoptive mothers. Moreover, the differences between birth and adoptive mother representations were found to associate with adoptees’ externalizing behaviors.