diff --git a/doc/release-notes-15637.md b/doc/release-notes-15637.md
new file mode 100644
index 0000000000..14fd7c00af
--- /dev/null
+++ b/doc/release-notes-15637.md
@@ -0,0 +1,3 @@
+RPC changes
+-----------
+In getmempoolancestors, getmempooldescendants, getmempoolentry and getrawmempool RPCs, to be consistent with the returned value and other RPCs such as getrawtransaction, vsize has been added and size is now deprecated. size will only be returned if dashd is started with `-deprecatedrpc=size`.
diff --git a/src/rpc/blockchain.cpp b/src/rpc/blockchain.cpp
index 21105f0ea1..ae83bb8fa1 100644
--- a/src/rpc/blockchain.cpp
+++ b/src/rpc/blockchain.cpp
@@ -438,7 +438,9 @@ static UniValue getdifficulty(const JSONRPCRequest& request)
 
 static std::string EntryDescriptionString()
 {
-    return "    \"size\" : n,                 (numeric) transaction size in bytes\n"
+    return "    \"vsize\" : n,                (numeric) virtual transaction size. This can be different from actual serialized size for high-sigop transactions.\n"
+           "    \"size\" : n,                 (numeric) (DEPRECATED) same as vsize. Only returned if dashd is started with -deprecatedrpc=size\n"
+           "                                  size will be completely removed in v0.20.\n"
            "    \"fee\" : n,                  (numeric) transaction fee in " + CURRENCY_UNIT + " (DEPRECATED)\n"
            "    \"modifiedfee\" : n,          (numeric) transaction fee with fee deltas used for mining priority (DEPRECATED)\n"
            "    \"time\" : n,                 (numeric) local time transaction entered pool in seconds since 1 Jan 1970 GMT\n"
@@ -475,7 +477,8 @@ static void entryToJSON(const CTxMemPool& pool, UniValue& info, const CTxMemPool
     fees.pushKV("descendant", ValueFromAmount(e.GetModFeesWithDescendants()));
     info.pushKV("fees", fees);
 
-    info.pushKV("size", (int)e.GetTxSize());
+    info.pushKV("vsize", (int)e.GetTxSize());
+    if (IsDeprecatedRPCEnabled("size")) info.pushKV("size", (int)e.GetTxSize());
     info.pushKV("fee", ValueFromAmount(e.GetFee()));
     info.pushKV("modifiedfee", ValueFromAmount(e.GetModifiedFee()));
     info.pushKV("time", e.GetTime());
diff --git a/test/functional/mempool_packages.py b/test/functional/mempool_packages.py
index accbc90251..da70fc31f7 100755
--- a/test/functional/mempool_packages.py
+++ b/test/functional/mempool_packages.py
@@ -58,9 +58,9 @@ class MempoolPackagesTest(BitcoinTestFramework):
         assert_equal(len(mempool), MAX_ANCESTORS)
         descendant_count = 1
         descendant_fees = 0
-        descendant_size = 0
+        descendant_vsize = 0
 
-        ancestor_size = sum([mempool[tx]['size'] for tx in mempool])
+        ancestor_vsize = sum([mempool[tx]['vsize'] for tx in mempool])
         ancestor_count = MAX_ANCESTORS
         ancestor_fees = sum([mempool[tx]['fee'] for tx in mempool])
 
@@ -79,15 +79,15 @@ class MempoolPackagesTest(BitcoinTestFramework):
             assert_equal(mempool[x]['fees']['modified'], mempool[x]['modifiedfee'])
             assert_equal(mempool[x]['descendantfees'], descendant_fees * COIN)
             assert_equal(mempool[x]['fees']['descendant'], descendant_fees)
-            descendant_size += mempool[x]['size']
-            assert_equal(mempool[x]['descendantsize'], descendant_size)
+            descendant_vsize += mempool[x]['vsize']
+            assert_equal(mempool[x]['descendantsize'], descendant_vsize)
             descendant_count += 1
 
             # Check that ancestor calculations are correct
             assert_equal(mempool[x]['ancestorcount'], ancestor_count)
             assert_equal(mempool[x]['ancestorfees'], ancestor_fees * COIN)
-            assert_equal(mempool[x]['ancestorsize'], ancestor_size)
-            ancestor_size -= mempool[x]['size']
+            assert_equal(mempool[x]['ancestorsize'], ancestor_vsize)
+            ancestor_vsize -= mempool[x]['vsize']
             ancestor_fees -= mempool[x]['fee']
             ancestor_count -= 1
 
diff --git a/test/functional/mining_prioritisetransaction.py b/test/functional/mining_prioritisetransaction.py
index 2a3f1f9cab..0c47c56bff 100755
--- a/test/functional/mining_prioritisetransaction.py
+++ b/test/functional/mining_prioritisetransaction.py
@@ -58,7 +58,7 @@ class PrioritiseTransactionTest(BitcoinTestFramework):
         for i in range(3):
             for j in txids[i]:
                 assert j in mempool
-                sizes[i] += mempool[j]['size']
+                sizes[i] += mempool[j]['vsize']
             assert sizes[i] > MAX_BLOCK_SIZE  # Fail => raise utxo_count
 
         # add a fee delta to something in the cheapest bucket and make sure it gets mined