The literature has shown the protective role of maternal Mind-mindedness (MM) on children's psychological adjustment and parenting stress and it has outlined the predictive effect of parenting stress on children's internalizing/externalizing behaviors. In 28 mother-child dyads (1 year), the present study explores whether maternal stress mediates the association between MM and children's internalizing/externalizing behaviors. PSI-SF and CBCL were administered to assess parenting stress and internalizing/externalizing behaviors. MM was evaluated through the observation of a mother-child play session. The results show that the dimension of stress «dysfunctional parent-child interaction» mediates between MM and internalizing behaviors while the stress «difficult child» mediates between MM and externalizing behaviors.