Methods and apparatus to implement scalable routing in network communication systems are disclosed. A disclosed example method involves selecting a plurality of virtual private networks in a communication network and selecting a candidate hub router from a plurality of routers in the communication network. The example method also involves determining a plurality of least memory utilization costs associated with assigning different quantities of spoke routers to the candidate hub router. Each of the least memory utilization costs and corresponding quantity of spoke routers is associated with a corresponding one of the plurality of virtual private networks. For each of the least memory utilization costs, a bandwidth usage of a corresponding one of the quantities of spoke routers is identified. The candidate hub router is selected to operate as a hub router for one of the quantities of spoke routers associated with a corresponding one of the bandwidth usages that does not exceed a bandwidth capacity of the candidate hub router.