In a short-term longitudinal design we investigated maternal sensitivity, child responsiveness, attachment, and indiscriminate friendliness in families with children internationally adopted from institutions or foster care in China. Ninety-two families with 50 postinstitutionalized and 42 formerly fostered girls, aged 11-16 months on arrival, were studied 2 and 6 months after adoption. Maternal sensitivity and child responsiveness were observed with the Emotional Availability Scales, attachment was assessed with the Strange Situation procedure, and mothers reported on children's indiscriminate friendliness. The postinstitutionalized children showed less secure attachment, whereas the former foster children did not differ from the normative distribution of attachment security. However, at both assessments the two groups of adopted children showed more disorganized attachments compared to normative data. Adoptive mothers of postinstitutionalized and former foster children were equally sensitive and their sensitivity did not change over time. Postinstitutionalized and former foster children did not differ on indiscriminate friendliness, but children with more sensitive adoptive mothers showed less indiscriminate friendliness. The former foster children showed a larger increase in responsiveness over time than the postinstitutionalized children, suggesting that children's responsiveness is more sensitive to change than attachment, and that preadoption foster care is more beneficial for the development of children's responsiveness after adoptive placement than preadoption institutional care.