Two studies examined the effects of breast-feeding on maternal stress and mood. In Experiment 1, perceived stress in the past month was compared between 28 breast-feeding and 27 bottle-feeding mothers. Breast-feeding mothers reported less perceived stress, after controlling for demographic confounds. In Experiment 2, mood ratings were assessed in the same 24 mothers both before and then after 1 breast-feeding and 1 bottle-feeding session. Breast-feeding was associated with a decrease in negative mood, and bottle-feeding was associated with a decrease in positive mood from pre- to postfeeding. Results indicated that breast-feeding buffers negative mood. These effects appeared to be attributable to the effects of breast-feeding itself and not solely to individual-differences factors.