Resumen:This study on children with a Pervasive Developmental Disorder (PDD; N= 32), children with developmental language disorder (N= 22), and normally developing children (N= 28) sought to answer questions concerning attachment and autistic behaviour. We could replicate the finding that children with a PDD are able to develop secure attachment relationships to their primary caregiver. Children withPDDwho had an insecure attachment showed fewer social initiatives and responses than children with PDD who had a secure attachment, even when the insecurely and securely attached PDD children were matched on chronological and mental age. Children with both a PDD and mental retardation were more often classified as disorganised. Three findings suggested that a disorganised attachment does not merely reflect the presence of “autistic” behaviour: (1) children with PDD did not reveal higher rates of a disorganised attachment than matched comparison children; (2) having a PDD diagnosis and having a disorganised attachment were found to be associated with opposite effects on an ethological measure of level of behavioural organisation; and (3) a disorganised attachment but not a PDD diagnosis was associated with an increase in heart rate during parting with the caregiver and a decrease in heart rate during reunion.