This study examines the question whether early childhood temperaments of children of mothers suffering from postnatal depression differs from children of non-depressed mothers. Children of clinically depressed mothers were assessed with regard to their temperament on two different dimensions and compared to a control group. The level of cortisol concentration in the children's saliva was the first variable. Saliva samples were gathered on three consecutive days to obtain a baseline, and before and after a mother-children interaction, which was interrupted by a still-face phase. As second variable the early childhood temperament was assessed with the Infant Behavior Questionnaire (IBQ). After the mother-children interaction the cortisol concentration levels of children of mothers suffering from postnatal depression were significantly lower. In the IBQ-Scales the children of depressed mothers showed significantly higher values on the scales Distress to Limitations and Activity. The significantly lower cortisol concentration in the saliva of children of mothers suffering from postpartum depression could be an indication that these children are already used to the fact that their mothers are not paying attention to them during the still-face phase. Overall, the results give rise to the assumption that postpartum depression does have an adverse impact on the development of affected children and that early intervention would be expedient to prevent the occurrence of pathological behavior characteristics and difficult mother-child relationships.