The purpose of this study was to explore early psychophysiologic mother-infant interaction using the tenderness and anxiety theorems of Harry Stack Sullivan. Maternal anxiety and perception were assessed and related to changes in infant satiety, anxiety, and feeding behavior. Sixty-five healthy post-partum, bottle-feeding mothers completed the Blank Infant Tenderness Scale and the State–Trait Anxiety Inventory. Blood samples were obtained from the infants just before and 60 minutes after feeding for determination of glucose and cortisol. Formula consumption was also noted. Multivariate analysis of variance demonstrated that maternal state–trait anxiety was related to infant glucose, cortisol, and formula consumption. In particular, mild maternal prefeed state anxiety was associated with lower infant cortisol difference scores, and extremely low maternal prefeed state anxiety was associated with higher infant cortisol difference scores. Mild maternal feed state anxiety, in turn, was associated with greater infant formula consumption, and extremely low maternal feed state anxiety was associated with lower formula consumption. Pearson correlations indicated a significant direct relationship between infant prefeed cortisol and postfeed glucose, but not between infant formula consumption and postfeed glucose.