Multicast route leaking between VRFs in different VPNs enables receivers in different VPNs to subscribe to the same IP multicast so that an efficient IP multicast distribution tree can be built to include subscribers in multiple VPNs. VRFs are administratively configured to implement multicast route leaking and each such configured VRF brings up an internal connectionless IP interface. The VRFs then enable the multicast routing protocol (e.g. PIM) on the internal IP interface to establish PIM neighborships with each other. When a VRF receives an IGMP join from a receiver, it uses PIM to join the receiver to the multicast over the internal IP interface. This enables receivers outside of a VPN but associated with VRFs that are co-located on the same PE to join multicasts established within the VPN so that separate multicast distribution trees are not required for each VPN.