The analysis of 11 home movies taken by parents before the recognition of autistic or atypical disorders of their own child has confirmed the major value of this method for describing early pathological signs. Symptomatology analysis has revealed anomalies of eye contact, a deficiency and variability of emotional expression, a defect of attention and initiation of communication, as well as motor abnormalities. The comparison of the frequency of abnormal behaviour, assessed with a rating scale among three groups of children (autistic, pervasive developmental disorders and normal) revealed behavioural differences as a function of early age and diagnosis, which concern not only social and communicative behaviours, but those of emotion and attention as well. The limits and interest of this methodological approach are discussed and the possibilities of subsequently using these documents in a more complete method, such as blind examination and scoring by uninformed investigators, are suggested.