This research explored the nature of early childhood practitioners' interpretations of infants in their programs on the basis that such interpretations guide practitioner-infant interactions and curriculum decision-making processes. Twenty-four infant practitioners were asked to describe a nominated infant in their program and to interpret video extracts of that infant's behaviour in the contexts of toy play and a nappy-change routine. Constant comparison techniques were employed to develop a model representing the theoretical properties of the ideas and explanations contained within their interpretive statements, and to identify main areas of individual or contextual variation. The findings extend current understandings of the psychological context of early childhood infant programs and provide a foundation for future investigations of the implications of infant practitioner interpretations for their professional teaching and caregiving practices. (Contains 1 table and 1 figure.)