The role of maternal sensitivity as a mediator accounting for the robust association between maternal attachment representations and the quality of the infant-mother attachment relationship was examined. Sixty mother-infant dyads were observed at home and in the Strange Situation at 13 months, and mothers participated in the Adult Attachment Interview (AAI) within the next 6 months. A strong association was found between AAI and Strange Situation classifications, and autonomous mothers were more sensitive at home than were nonautonomous mothers. Mothers in secure relationships were more sensitive at home than mothers in nonsecure relationships. Likewise, infants in secure relationships were more secure as assessed by the Waters' Attachment Q sort than infants in nonsecure relationships. A test of the mediational model revealed that maternal sensitivity accounted for 17% of the relation between AAI and Strange Situation classifications.