diff --git a/eth/chains/ropsten/__init__.py b/eth/chains/ropsten/__init__.py
index 9c07ac878c..c778320fe3 100644
--- a/eth/chains/ropsten/__init__.py
+++ b/eth/chains/ropsten/__init__.py
@@ -5,6 +5,7 @@
 from .constants import (
     BYZANTIUM_ROPSTEN_BLOCK,
     CONSTANTINOPLE_ROPSTEN_BLOCK,
+    ISTANBUL_ROPSTEN_BLOCK,
     PETERSBURG_ROPSTEN_BLOCK,
     ROPSTEN_CHAIN_ID,
     SPURIOUS_DRAGON_ROPSTEN_BLOCK,
@@ -18,6 +19,7 @@
 from eth.vm.forks import (
     ByzantiumVM,
     ConstantinopleVM,
+    IstanbulVM,
     PetersburgVM,
     SpuriousDragonVM,
     TangerineWhistleVM,
@@ -31,6 +33,7 @@
     (BYZANTIUM_ROPSTEN_BLOCK, ByzantiumVM),
     (CONSTANTINOPLE_ROPSTEN_BLOCK, ConstantinopleVM),
     (PETERSBURG_ROPSTEN_BLOCK, PetersburgVM),
+    (ISTANBUL_ROPSTEN_BLOCK, IstanbulVM),
 )
 
 
diff --git a/eth/chains/ropsten/constants.py b/eth/chains/ropsten/constants.py
index 9aac781416..9523f89430 100644
--- a/eth/chains/ropsten/constants.py
+++ b/eth/chains/ropsten/constants.py
@@ -46,3 +46,9 @@
 # Petersburg
 #
 PETERSBURG_ROPSTEN_BLOCK = BlockNumber(4939394)
+
+
+#
+# Istanbul
+#
+ISTANBUL_ROPSTEN_BLOCK = BlockNumber(6485846)
diff --git a/newsfragments/1851.feature.rst b/newsfragments/1851.feature.rst
new file mode 100644
index 0000000000..41393ed423
--- /dev/null
+++ b/newsfragments/1851.feature.rst
@@ -0,0 +1 @@
+enable Istanbul fork on Ropsten chain