This article presents two types of networks organized according to patient caseload in health services, concerning both primary hospital care (most frequent hospital procedures) and tertiary care (high-cost procedures). Data on inpatient care in Brazil in 2000 obtained from the Hospital Information System of the Unified National Health System were aggregated by place of residence and hospital location at the municipal level. Both the network structure and the node (municipality) hierarchy were established using the dominant flow approach. In addition, a typology of flows was applied to indicate the degree of connection across the networks. Primary hospital care networks reach most of the country, and few municipalities are not connected to the network. Relatively few cities provide higher-level services, and almost half of the municipalities are unconnected. The Ministry of Health aims to provide access to frequently used health services near the users' place of residence, and this goal appears to be feasible in the short run. On the other hand, much remains to be done to ensure widespread access to tertiary care.