Serious disturbances of attachment in young children have been increasingly studied in the past decade as they arise in atypical rearing environments. The purpose of this review is to provide an update on recent findings and to consider their implications. Research on children raised in institutions, children adopted out of institutions, and young children who have experienced neglect in families is considered. Reactive attachment disorder may be identified reliably in a minority of children being raised in severely neglectful environments. The emotionally withdrawn/inhibited pattern and the indiscriminately social/disinhibited pattern arise in similar conditions of risk, but respond differently to intervention and appear to have different correlates. Much has been learned about the emotionally withdrawn/inhibited pattern of reactive attachment disorder and the indiscriminately social/disinhibited pattern. Much less is known about so-called secure base distortions or relational disorders of attachment.