This study examined the relation of low income and poverty to cortisol levels, and tested potential pathways from low income to disruptions in cortisol through cumulative family risk and parenting. The sample of 306 mothers and their preschool children included 29 % families at or near poverty, 27 % families below the median income, and the remaining families at middle and upper income. Lower income was related to lower morning cortisol levels, and cumulative risk predicted a flatter diurnal slope, with a significant indirect effect through maternal negativity, suggesting that parenting practices might mediate an allostatic effect on stress physiology.