Oxytocin is a neuropeptide associated with social affiliation and maternal caregiving. However, its effects appear to be moderated by various contextual factors and stable individual characteristics. The purpose of this study was to investigate the relationship of self-reported state and trait measures (such as temperament, mood and affect) with peripheral oxytocin response in mothers. Fifty-five first-time mothers participated in a semi-structured procedure, during which time repeated peripheral oxytocin levels were measured before, during and after an episode of mother–infant interaction. The maternal oxytocin response was then calculated, based on the difference in oxytocin concentration between initial baseline and interaction phase. Mothers also completed state measures of positive and negative affect and depression, and trait measures of temperament, personality disturbance and depression across time. Regression analyses determined which factors were independently associated with maternal oxytocin response. The trait measure of adult temperament emerged as a significant predictor of oxytocin response. Two out of four Adult Temperament Questionnaire factor scales were independently associated with oxytocin response: Effortful Control was negatively associated, whereas Orienting Sensitivity was positively associated. No state measure significantly predicted oxytocin response. The results indicate that mothers who show an increased oxytocin response when interacting with their infants are more sensitive of moods, emotions and physical sensations; and less compulsive, schedule driven and task oriented. These findings link differences in individual temperament in new mothers with the peripheral oxytocin response, which may have implications in the pharmacologic treatment of disorders such as maternal neglect, post-partum depression and maternal addiction.This article is part of a Special Issue entitled Oxytocin, Vasopressin, and Social Behavior.