Defiant behavior in two- and three-year-olds is a natural expression of a young child's growing autonomy, and, although frustrating to adults, is a natural phase of a child's socio-emotional growth. L.S. Vygotsky's socio-historical theory of the development included a discussion of "crisis" periods, one of which he felt occurred at age three. The crisis that Vygotsky asserted occurred at three is characterized by a group of seven "behaviors", all of which indicate a struggle with the child's position in relation to family social structures. This study examined the occurrences and characteristics of defiant behavior in two- and three-year-old children during outdoor play at a child development center, and the existence and context of defiant behaviors the modern childcare setting. Patterns in defiant behaviors during play in different age groups were apparent, and suggested an instrument to facilitate the documentation and analysis of defiant behavior in modern group-care settings.