A study of the prognosis for walking of 73 pre-school children who had cerebral palsy or delayed motor development is reported. The importance of prognostic signs, based upon the presence or absence of postural reflex activity, was confirmed. The prognosis was accurate in 94-5 per cent of the 73 children studied. The method of scoring a child's reflex responses and relating this to the prognosis seems to be a simple procedure, easy to understand and to apply. It is suggested that the assessment of treatment methods should include an analysis of the child's walking potential, based upon the methods delineated in this study, before treatment is started.