Summary: Past studies of the Internal Revenue Service (IRS) have concluded that the agency needs regional offices. GAO reached the same conclusion after surveying the internal customers of regional offices--executives in IRS' National Office and field offices--and after reviewing regional office involvement in IRS' new initiative aimed at bringing nonfilers back into the tax system. IRS has about 96,000 field office workers spread over about 700 locations. Evidence suggests that regional offices are needed for effective management of such a large and far-flung organization. However, GAO found that these offices are not functioning in a way that yields the greatest returns to internal customers. Many customers, although acknowledging the need for regional offices, often responded negatively to questions about how helpful regional offices have been. With that in mind and in conjunction with upcoming changes that will shrink the number and size of regional offices, IRS needs to rethink the role of those offices. For example, regional staff should not spend valuable time funneling information between national and field offices or doing unproductive reviews of field office activities. It is also unproductive for regional offices to manage activities, such as returns processing, in which the number of sites involved is small enough for the National Office to manage directly.