Background: Children with intellectual disability (ID) are at risk for maladaptive development of social relatedness. Controversy exists whether Pervasive Developmental Disorder (PDD) takes precedence over disordered attachment for describing maladaptive social behaviour. The aim of this study was to assess the prevalence of disordered attachment symptoms in children with ID referred for mental health diagnosis, and to study the potential diagnostic overlap between symptoms of disordered attachment and PDD symptoms. Method: Children (n?=?102) in the age of 5-11 with IDs (borderline or mild; IQ 50-85) referred for psychiatric consultation were recruited. Parents were administered a screening interview for disturbances of attachment and teachers were administered a screening questionnaire for PDD. Results: Behavioural symptoms of disordered attachment were reported for 42%*- of the children, with 16%*- showing symptoms of inhibited and 37%*- showing symptoms of disinhibited attachment disorder. In 11% both types of symptoms were noted. Attachment disorder symptoms were not significantly associated with gender, ethnic background or age. Positive screening for PDD occurred for 27%. Positive screening for PDD was not significantly associated with symptoms of attachment disorder. Conclusions: Among children with ID referred for psychiatric consultation, Reactive Attachment Disorder (RAD) and PDD symptoms were both highly prevalent. RAD and PDD symptoms appear as distinct, but sometimes comorbid, forms of aberrant social relatedness.