According to one aspect, the subject matter described herein includes a method for screening Diameter messages within a Diameter signaling router (DSR) having a distributed message processor architecture. The method includes steps occurring at a DSR comprising a plurality of Diameter message processors, each configured to perform at least one Diameter function. The steps include receiving, at an ingress Diameter message processor of the Diameter message processors, a Diameter message from a Diameter peer node. The steps also include identifying, at a Diameter application message processor of the Diameter message processors, a Diameter message screening rule associated with the received Diameter message. The steps further include performing, at the Diameter application message processor of the Diameter message processors, a screening function associated with the identified Diameter message screening rule on the received Diameter message.