Young children who have experienced early adversity are at risk for developing disorganized attachments. The efficacy of Attachment and Biobehavioral Catch-up (ABC), an intervention targeting nurturing care among parents identified as being at risk for neglecting their young children, was evaluated through a randomized clinical trial. Attachment quality was assessed in the Strange Situation for 120 children between 11.7 and 31.9 months of age (M = 19.1, SD = 5.5). Children in the ABC intervention showed significantly lower rates of disorganized attachment (32%) and higher rates of secure attachment (52%) relative to the control intervention (57% and 33%, respectively). These results support the efficacy of the ABC intervention in enhancing attachment quality among parents at high risk for maltreatment.