Leave-taking behavior of 84 pre-school children (44 female, 40 male) and their parents during separation at the beginning of a pre-school experience was studied. Super-8mm motion picture film was analyzed on a hand operated movie editor allowing a precise record of the segments of behavior to be made. Three factors emerged from the analysis: (1) the pre-school teacher facilitates parent-child separation, (2) warm parent-child affiliative behavior encourages mutually initiated separation, (3) reluctance of the child to separate from a rejecting parent who does not respond with affiliative behavior. Traditional mother-infant attachment theory has limited utility for interpreting the findings. For the majority of the children transition from parent to pre-school was made easily. (Author)