The purpose of this study was to examine the relations among infant temperament, attachment, and behavioral inhibition. 52 infants were seen at 2 days, 5, 14, and 24 months of age. Assessments were made of temperament at 2 days and 5 months of age, and attachment and behavioral inhibition were assessed at 14 and 24 months, respectively. EKG was recorded at each assessment, and measures of heart period and vagal tone were computed. Distress to pacifier withdrawal at 2 days of age was related to insecure attachment at 14 months. 2 types of distress reactivity at 5 months, reactivity to frustration and reactivity to novelty, were identified and related to high vagal tone. Attachment classification at 14 months was directly related to inhibited behavior at 24 months. Infants classified as insecure/resistant were more inhibited than those classified as insecure/avoidant. In addition, an interaction of infant reactivity to frustration and attachment classification was found to predict inhibition at 24 months. Infants classified as insecure/resistant and who had not cried to the arm restraint procedure at 5 months were the most inhibited at 24 months. These findings are discussed in terms of hypotheses regarding multiple modes of distress reactivity and regulation in early infancy and their different social and behavioral outcomes.