diff --git a/qa/rpc-tests/replace-by-fee.py b/qa/rpc-tests/replace-by-fee.py
index ba1956853aa..999317b449f 100755
--- a/qa/rpc-tests/replace-by-fee.py
+++ b/qa/rpc-tests/replace-by-fee.py
@@ -82,7 +82,8 @@ class ReplaceByFeeTest(BitcoinTestFramework):
                                                               "-limitancestorcount=50",
                                                               "-limitancestorsize=101",
                                                               "-limitdescendantcount=200",
-                                                              "-limitdescendantsize=101"
+                                                              "-limitdescendantsize=101",
+                                                              "-mempoolreplacement=1"
                                                               ]))
         self.is_network_split = False