Individual service/support plans from several different agencies were integrated to improve coordination and service delivery, and address difficulties encountered by families whose children are served by multiple agencies. Components of the Interagency Planning and Support model are described, and data on the development, adoption, and utilization of the Collaborative Support Plan (CSP) are presented from a sample of 34 families and 49 providers. Analysis of project level, parent, provider, and administrative data revealed the approach was successful in producing an integrated service plan that was valued by participants and was determined by parents to be better than previous service planning experiences. Factors affecting the success of development, adoption, and utilization of this innovative approach are described.