Children of mothers with depressive symptoms often have high cortisol levels. Research shows that various child characteristics (e.g., attachment pattern, internalizing behaviours, and temperament) moderate this association. We suggest that these characteristics share common variance with emotion regulation strategy. Therefore, we examine infant emotion regulation strategy as a moderator of the association between maternal depressive symptoms and infant hypothalamic-pituitary-adrenal (HPA) function. We hypothesize that infants who utilize more independent emotion regulation strategies and have mothers who report higher depressive symptoms will exhibit elevated cortisol levels. Participants were 193 mothers and infants (15?months old) recruited from the community. Self-reported maternal depressive symptoms were assessed. Infant independent regulatory behaviours (withdrawal, wandering away, distraction, scanning, orienting to another object) were coded in the context of a Toy Frustration Task. Infant cortisol was collected via saliva samples at baseline, +20, and +40?minutes. Results indicate that infant emotion regulation strategy moderates the relation between mothers' self-reported depressive symptoms and infant total cortisol output (AUCG) and cortisol reactivity (AUCI). Infants who employed more independent regulatory behaviours and have mothers with higher depressive symptoms experience greater cortisol secretion. We discuss the findings in relation to parent-infant interactions and the adaptive nature of emotion regulation strategies, as they relate to HPA regulatory capacities.