Infancy and early childhood sleep–wake behaviours from current and retrospective parental reports were used to explore the relationship between sleeping arrangements and parent–child nighttime interactions at both time points. Children (N=45) from educated, middle-class families, mostly breastfed in infancy, composed a convenience sample that was recruited from a university preschool in the Northeast US. Parents responded to the Sleep Habits Inventory, a 19-item Likert-style inventory measuring sleep-related behaviours during the last week, and the Sleeping Arrangements Questionnaire, a 30-question, open-ended, short-answer-style instrument which queries both retrospective infancy and current sleep location, bedtime routine, night waking and parent–child interactions during the sleep period. Co-sleeping in early childhood was associated with sleep location in infancy (i.e. proximity to the mother's bed) during wake–sleep transitions and night feedings. Security object use during infancy was inversely related to early childhood co-sleeping (calling for the parents, night waking, poor bedtime routine and fear of the dark). Results showed that early childhood co-sleeping in this sample was reactive, i.e. associated with current parent-seeking, night waking and social contact during wake–sleep transitions. These findings suggest that co-sleeping in early childhood is related to social experiences during infancy, particularly the amount of parent social contact and security object use. Copyright © 2007 John Wiley & Sons, Ltd.