Developmental programming of the hypothalamic-pituitary-adrenal axis is theorized as a mechanism through which early life experiences are linked to later health outcomes. Despite the importance of understanding early stress responses, reliably eliciting stress responses in young children can be challenging. The current study measured salivary cortisol reactivity in a diverse sample of preschoolers. A standardized challenge paradigm was administered at home and at child care for each child, allowing for comparison of normative cortisol reactivity between settings. Results demonstrated that administration at home was associated with significant cortisol reactivity, while administration at child care was not. In comparison to white children, racially and ethnically diverse children exhibited lower cortisol reactivity in response to the home stressor. Results suggest that home-based stress paradigms may be particularly effective at eliciting a stress response in this age range. Possible interpretations of differences by child race/ethnicity are discussed.