Collaboration between welfare and child welfare agencies is important because there is significant overlap in the clients the two agencies serve. This "dual-system" population struggles with both poverty and child abuse or neglect. Based on visits to county agencies in 13 states, the authors provide specific examples of three types of collaborative efforts: casework practice (collaborative efforts on the front line), program development (joint efforts to create new programs and services), and organizational infrastructure (how the system supports collaborative casework and programs). The seven factors that affect collaborative efforts include agency history and politics, leadership and policy direction, resource availability, information systems, colocation of workers from both agencies in a single office, staffing and workload, confidentiality, and palpable payoffs to workers.