diff --git a/src/main/java/org/qortal/transaction/ChatTransaction.java b/src/main/java/org/qortal/transaction/ChatTransaction.java
index 9cccd42a..b4ae9f37 100644
--- a/src/main/java/org/qortal/transaction/ChatTransaction.java
+++ b/src/main/java/org/qortal/transaction/ChatTransaction.java
@@ -19,6 +19,7 @@ import org.qortal.repository.Repository;
 import org.qortal.transform.TransformationException;
 import org.qortal.transform.transaction.ChatTransactionTransformer;
 import org.qortal.transform.transaction.TransactionTransformer;
+import org.qortal.utils.NTP;
 
 public class ChatTransaction extends Transaction {
 
@@ -145,6 +146,11 @@ public class ChatTransaction extends Transaction {
 	public ValidationResult isValid() throws DataException {
 		// Nonce checking is done via isSignatureValid() as that method is only called once per import
 
+		// Disregard messages with timestamp too far in the future (we have stricter limits for CHAT transactions)
+		if (this.chatTransactionData.getTimestamp() > NTP.getTime() + (5 * 60 * 1000L)) {
+			return ValidationResult.TIMESTAMP_TOO_NEW;
+		}
+
 		// Check for blocked author by address
 		ResourceListManager listManager = ResourceListManager.getInstance();
 		if (listManager.listContains("blockedAddresses", this.chatTransactionData.getSender(), true)) {