diff --git a/send-transaction-service/src/send_transaction_service.rs b/send-transaction-service/src/send_transaction_service.rs
index 86508297d..2ac8b617a 100644
--- a/send-transaction-service/src/send_transaction_service.rs
+++ b/send-transaction-service/src/send_transaction_service.rs
@@ -6,7 +6,7 @@ use {
     solana_runtime::{bank::Bank, bank_forks::BankForks},
     solana_sdk::{hash::Hash, nonce_account, pubkey::Pubkey, signature::Signature},
     std::{
-        collections::HashMap,
+        collections::hash_map::{Entry, HashMap},
         net::{SocketAddr, UdpSocket},
         sync::{Arc, RwLock},
         thread::{self, Builder, JoinHandle},
@@ -142,30 +142,36 @@ impl SendTransactionService {
                     Err(RecvTimeoutError::Timeout) => {}
                     Ok(transaction_info) => {
                         inc_new_counter_info!("send_transaction_service-recv-tx", 1);
-                        let addresses = leader_info.as_ref().map(|leader_info| {
-                            leader_info.get_leader_tpus(config.leader_forward_count)
-                        });
-                        let addresses = addresses
-                            .map(|address_list| {
-                                if address_list.is_empty() {
-                                    vec![&tpu_address]
-                                } else {
-                                    address_list
-                                }
-                            })
-                            .unwrap_or_else(|| vec![&tpu_address]);
-                        for address in addresses {
-                            Self::send_transaction(
-                                &send_socket,
-                                address,
-                                &transaction_info.wire_transaction,
-                            );
-                        }
-                        if transactions.len() < MAX_TRANSACTION_QUEUE_SIZE {
-                            inc_new_counter_info!("send_transaction_service-insert-tx", 1);
-                            transactions.insert(transaction_info.signature, transaction_info);
+                        let transactions_len = transactions.len();
+                        let entry = transactions.entry(transaction_info.signature);
+                        if let Entry::Vacant(_) = entry {
+                            let addresses = leader_info.as_ref().map(|leader_info| {
+                                leader_info.get_leader_tpus(config.leader_forward_count)
+                            });
+                            let addresses = addresses
+                                .map(|address_list| {
+                                    if address_list.is_empty() {
+                                        vec![&tpu_address]
+                                    } else {
+                                        address_list
+                                    }
+                                })
+                                .unwrap_or_else(|| vec![&tpu_address]);
+                            for address in addresses {
+                                Self::send_transaction(
+                                    &send_socket,
+                                    address,
+                                    &transaction_info.wire_transaction,
+                                );
+                            }
+                            if transactions_len < MAX_TRANSACTION_QUEUE_SIZE {
+                                inc_new_counter_info!("send_transaction_service-insert-tx", 1);
+                                entry.or_insert(transaction_info);
+                            } else {
+                                datapoint_warn!("send_transaction_service-queue-overflow");
+                            }
                         } else {
-                            datapoint_warn!("send_transaction_service-queue-overflow");
+                            inc_new_counter_info!("send_transaction_service-recv-duplicate", 1);
                         }
                     }
                 }