Methods, systems, and computer readable media for performing stateful Diameter routing with Diameter routing agents (DRAs) using different mechanisms to achieve stateful routing are disclosed. According to one aspect, a system for performing stateful Diameter routing with DRAs that use different mechanisms to achieve stateful routing includes a set of Diameter signaling routing nodes. Each node has access to at least one database for maintaining state information. The nodes are configured to be members of a first group, where each member of the first group is configured to use a first mechanism to achieve stateful routing with other members of the first group, and to use a second mechanism to achieve stateful routing with nodes that are not members of the first group. Members of the first group include signaling nodes provided by a same vendor, and members not in the group include signaling nodes provided by a different vendor.