Quantitative as well as qualitative aspects of the social behaviour of a group of autistic children (n = 20) and a group of primary school children (n = 20) were studied by means of an ethological method. Principal components analysis of the behaviour protocols made clear that the social behaviour of autistic children was less well organized, lacked the factor 'inferential behaviour' and was characterized by a factor 'stereotyped behaviour'. Although the autistic group showed less eye contact than the normal group, no further signs of any particular social avoidance tendency was found.