diff --git a/crates/mempool/src/lib.rs b/crates/mempool/src/lib.rs
index fb92ed2d..6d5d6f00 100644
--- a/crates/mempool/src/lib.rs
+++ b/crates/mempool/src/lib.rs
@@ -1,2 +1,3 @@
 pub mod mempool;
 pub(crate) mod priority_queue;
+pub mod transaction_store;
diff --git a/crates/mempool/src/mempool.rs b/crates/mempool/src/mempool.rs
index 6da16953..3916b80f 100644
--- a/crates/mempool/src/mempool.rs
+++ b/crates/mempool/src/mempool.rs
@@ -16,6 +16,7 @@ use starknet_mempool_types::mempool_types::{
 use tokio::select;
 
 use crate::priority_queue::TransactionPriorityQueue;
+use crate::transaction_store::TransactionStore;
 
 #[cfg(test)]
 #[path = "mempool_test.rs"]
@@ -26,6 +27,7 @@ pub struct Mempool {
     pub gateway_network: MempoolNetworkComponent,
     batcher_network: BatcherToMempoolChannels,
     txs_queue: TransactionPriorityQueue,
+    tx_store: TransactionStore,
     state: HashMap<ContractAddress, AccountState>,
 }
 
@@ -37,6 +39,7 @@ impl Mempool {
     ) -> Self {
         let mut mempool = Mempool {
             txs_queue: TransactionPriorityQueue::default(),
+            tx_store: TransactionStore::default(),
             state: HashMap::default(),
             gateway_network,
             batcher_network,
@@ -58,6 +61,15 @@ impl Mempool {
                         input.account.address,
                         input.tx
                     );
+
+                    // Insert the transaction into the tx_store.
+                    let res = mempool.tx_store.push(input.tx.clone());
+                    assert!(
+                        res.is_ok(),
+                        "Transaction: {:?} already exists in the mempool.",
+                        input.tx.tx_hash
+                    );
+
                     input.tx
                 })
                 .collect::<Vec<ThinTransaction>>(),
@@ -82,6 +94,7 @@ impl Mempool {
         let txs = self.txs_queue.pop_last_chunk(n_txs);
         for tx in &txs {
             self.state.remove(&tx.sender_address);
+            self.tx_store.remove(&tx.tx_hash)?;
         }
 
         Ok(txs)
@@ -95,7 +108,9 @@ impl Mempool {
             Occupied(_) => Err(MempoolError::DuplicateTransaction { tx_hash: tx.tx_hash }),
             Vacant(entry) => {
                 entry.insert(account.state);
-                self.txs_queue.push(tx);
+                self.txs_queue.push(tx.clone());
+                self.tx_store.push(tx)?;
+
                 Ok(())
             }
         }
diff --git a/crates/mempool/src/transaction_store.rs b/crates/mempool/src/transaction_store.rs
new file mode 100644
index 00000000..a01a9667
--- /dev/null
+++ b/crates/mempool/src/transaction_store.rs
@@ -0,0 +1,46 @@
+use std::collections::{BTreeMap, HashMap};
+
+use starknet_api::core::{ContractAddress, Nonce};
+use starknet_api::transaction::TransactionHash;
+use starknet_mempool_types::errors::MempoolError;
+use starknet_mempool_types::mempool_types::ThinTransaction;
+
+#[derive(Clone, Debug, Default)]
+pub struct TransactionStore {
+    store: HashMap<ContractAddress, BTreeMap<Nonce, ThinTransaction>>,
+    tx_hash_2_tx: HashMap<TransactionHash, (ContractAddress, Nonce)>,
+}
+
+impl TransactionStore {
+    pub fn push(&mut self, tx: ThinTransaction) -> Result<(), MempoolError> {
+        let account_store = self.store.entry(tx.sender_address).or_default();
+        // TODO(Mohammad): Allow overriding a previous transaction.
+        if account_store.contains_key(&tx.nonce) {
+            return Err(MempoolError::DuplicateTransaction { tx_hash: tx.tx_hash });
+        }
+        account_store.insert(tx.nonce, tx.clone());
+        self.tx_hash_2_tx.insert(tx.tx_hash, (tx.sender_address, tx.nonce));
+        Ok(())
+    }
+
+    pub fn remove(&mut self, tx_hash: &TransactionHash) -> Result<ThinTransaction, MempoolError> {
+        if let Some((address, nonce)) = self.tx_hash_2_tx.remove(tx_hash) {
+            if let Some(tree_map) = self.store.get_mut(&address) {
+                if let Some(tx) = tree_map.remove(&nonce) {
+                    return Ok(tx);
+                }
+            }
+        }
+        Err(MempoolError::TransactionNotFound { tx_hash: *tx_hash })
+    }
+
+    pub fn get(&mut self, tx_hash: &TransactionHash) -> Result<&ThinTransaction, MempoolError> {
+        let (address, nonce) = self.tx_hash_2_tx.get(tx_hash).unwrap();
+        if let Some(tree_map) = self.store.get(address) {
+            if let Some(tx) = tree_map.get(nonce) {
+                return Ok(tx);
+            }
+        }
+        Err(MempoolError::TransactionNotFound { tx_hash: *tx_hash })
+    }
+}
diff --git a/crates/mempool_types/src/errors.rs b/crates/mempool_types/src/errors.rs
index bdc458b2..ff676545 100644
--- a/crates/mempool_types/src/errors.rs
+++ b/crates/mempool_types/src/errors.rs
@@ -5,4 +5,6 @@ use thiserror::Error;
 pub enum MempoolError {
     #[error("Duplicate transaction, of hash: {tx_hash}")]
     DuplicateTransaction { tx_hash: TransactionHash },
+    #[error("Transaction of hash: {tx_hash} is not found")]
+    TransactionNotFound { tx_hash: TransactionHash },
 }