Establishing the adequacy or inadequacy of the supply of physical therapists, nationally and across geographic areas, has important policy implications for federal support of education and training of physical therapists. This article summarizes research that was undertaken to determine 1) whether physical therapists are in short supply nationally, or are geographically maldistributed in the United States, and 2) if there is an uneven distribution, whether it is possible to identify areas lacking physical therapists. The supply of physical therapists at the county level is examined in relation to factors presumed to indicate need for physical therapy services. Next, the distribution of physical therapists is examined in selected groups of counties to determine why some areas are relatively better supplied than others and whether any obvious set of criteria accurately and consistently identifies those areas appearing underserved. The major conclusion is there may be a maldistribution of physical therapist. Criteria for identifying shortages are recommended.