Developmental and behavioural characteristics were assessed in 27 children with cri du chat syndrome using the Society for the Study of Behavioural Phenotypes questionnaire, which gave information on prenatal and perinatal conditions, neurological problems, and developmental and behavioural difficulties. The findings suggest that the behavioural profile of children with cri du chat syndrome incorporates self injurious behaviour, repetitive movements, hypersensitivity to sound, clumsiness, and obsessive attachments to objects. In terms of a developmental profile, children with cri du chat syndrome were able to communicate their needs, socially interact with others, and have some degree of mobility.