Although social service privatization and performance contracting have increased over recent decades, there is a dearth of information concerning how public and private social service administrators manage performance contracts and develop collaborative relationships that promote desired client outcomes. The Quality Improvement Center on the Privatization of Child Welfare Services (QICPCW) was funded by the federal Children's Bureau to promote knowledge development regarding public/private contracting in child welfare. This article reports on results from interviews with a national sample of public agency administrators by the QICPCW regarding the scope and mechanisms of contracting in the child welfare sector. Results identify key administrative and agency practices that public and private agency administrators used to develop public/private collaborations and sustain effective cross-sector partnerships. Implications for social service administrative practice and research are identified.