Some young children are not merely insecurely attached and at risk for later problems; by virtue of the severity of their attachment disturbances they are already disordered. This article reviews and critiques the approaches of the Diagnostic and Statistical Manual of Mental Disorders (4th ed.; DSM-IV; American Psychiatric Association, 1994) and the International Classification of Diseases (10th ed.; ICD-10; World Health Organization, 1992) to attachment disorders and finds that they have not made use of findings from developmental research on attachment in developing their criteria. An alternative system of classifying attachment disorders that is compatible with the major findings from developmental research on infant-caregiver attachment is presented. Finally, many areas in need of empirical contributions are indicated. Ethological attachment theory, as outlined by John Bowlby (Bowlby, 1969, 1973, 1980), has provided one of the most important frameworks for understanding crucial risk and protective factors in social and emotional development in the first 3 years of life. Bowlby's (1951) monograph, Maternal Care and Mental Health, reviewed the world literature on maternal deprivation and suggested that emotionally available caregiving was crucial for infant development and mental health. Developmental attachment research, which has formally evaluated Bowlby's major premises, has demonstrated convincingly that insecure attachment in infancy is associated with subsequent psychosocial maladaptation in preschool and middle