This brief discusses how school districts nationwide are dealing with the challenges of the No Child Left Behind Act (NCLB). To understand how districts are reacting to NCLB, the researchers interviewed staff, visited websites, and examined other documentation from districts across the country and from national and regional education organizations. The research identified four main areas or concern about district-level NCLB implementation. First, within their overall efforts to turn around low-performing schools, districts are particularly concerned with NCLB requirements of providing students with supplemental services and public school choice when their schools do not make adequate yearly progress. Second, districts are concerned with ensuring that their teachers are highly qualified and their paraprofessionals are adequately trained. Third, districts want to build data capacity to expand data collection, use, and reporting. Fourth, districts also express concern about the adequacy of financial resources to carry out the mandates of NCLB. (WFA)