We present a membership protocol for the iTrust search and retrieval network. In iTrust, a source node distributes metadata together with the URL for a document to a subset of randomly chosen nodes in its local view of the membership. A requesting node distributes a request (query) containing keywords to a subset of randomly chosen nodes in its local view of the membership. If a node receives a request such that the keywords in the request match metadata that it holds, then it sends to the requesting node a response containing the URL, so that the requesting node can retrieve the document from the source node. The membership protocol for iTrust allows each member to have its own local view of the membership. A requesting node detects a non-operational node by not receiving a response from that node within a timeout, or by receiving an error code from TCP. Likewise, a requesting node discovers a newly joined node when it receives a response from a node that has included that newly joined node in its view. Our performance evaluation demonstrates that, for appropriate values of the parameters, the iTrust membership protocol discovers joining nodes and detects leaving nodes to maintain a local view of the membership that is close to the actual membership.