diff --git a/koinos/rpc/mempool/mempool_rpc.proto b/koinos/rpc/mempool/mempool_rpc.proto
index ee868a4..e7548e0 100644
--- a/koinos/rpc/mempool/mempool_rpc.proto
+++ b/koinos/rpc/mempool/mempool_rpc.proto
@@ -52,6 +52,15 @@ message get_reserved_account_rc_response {
    uint64 rc = 1;
 }
 
+message get_pending_nonce_request {
+   bytes payee = 1 [(btype) = ADDRESS];
+   optional bytes block_id = 2 [(btype) = BLOCK_ID];
+}
+
+message get_pending_nonce_response {
+   bytes nonce = 1;
+}
+
 message mempool_request {
    oneof request {
       rpc.reserved_rpc reserved = 1;
@@ -59,6 +68,7 @@ message mempool_request {
       get_pending_transactions_request get_pending_transactions = 3;
       check_account_nonce_request check_account_nonce = 4;
       get_reserved_account_rc_request get_reserved_account_rc = 5;
+      get_pending_nonce_request get_pending_nonce = 6;
    }
 }
 
@@ -70,5 +80,6 @@ message mempool_response {
       get_pending_transactions_response get_pending_transactions = 4;
       check_account_nonce_response check_account_nonce = 5;
       get_reserved_account_rc_response get_reserved_account_rc = 6;
+      get_pending_nonce_response get_pending_nonce = 7;
    }
 }