The bonding experiences and attachment patterns of 12 adopted and 12 nonadopted 1-year-old infants were compared in order to test the hypothesis that an infant who is not able to bond with his or her primary caregiver soon after birth is at higher risk for the formation of insecure attachment relationships. Attachment of infants to their mothers was assessed according to the strange situation procedure designed by Ainsworth and Wittig (1969). All 12 of the nonadopted infants were classified as securely attached, whereas almost half of the adopted infants were classified as anxious avoidant. In comparison with adoptive mothers of anxious avoidant infants, adoptive mothers of securely attached infants reported having spent three times as many hours with their infants during the first day of placement. The data suggest that the first 24 hours after placement may be a sensitive period in the formation of a bond between the adoptive mother and infant. For some infants, the adoptive experience itself significantly increases the risk of subsequent attachment problems. (Author/RH)