Breaking the Cycle (BTC), founded in 1995, is an early identification, prevention, and treatment program for pregnant and parenting women who abuse substances. The authors explore the impact of substance abuse on early attachment relationships and on infant regulatory functioning. BTC focuses on building and enhancing the mother's relationships, delivering a range of services through a single-access model with street outreach and home visitation components. The success of BTC indicates that modeling supportive relationships helps mothers increase their capacity for healthy and satisfying relationships, leading to positive mother-child interactions and more secure infants and children.