diff --git a/crypto/networks/mainnet.py b/crypto/networks/mainnet.py
index 9fa8ad1..cf4956a 100644
--- a/crypto/networks/mainnet.py
+++ b/crypto/networks/mainnet.py
@@ -2,7 +2,7 @@
 
 class Mainnet(AbstractNetwork):
     def chain_id(self):
-        return 10000
+        return 11811
 
     def epoch(self):
         return '2017-03-21T13:00:00.000Z'
diff --git a/crypto/networks/testnet.py b/crypto/networks/testnet.py
index 56995c1..c55b6ea 100644
--- a/crypto/networks/testnet.py
+++ b/crypto/networks/testnet.py
@@ -2,7 +2,7 @@
 
 class Testnet(AbstractNetwork):
     def chain_id(self):
-        return 10000
+        return 11812
 
     def epoch(self):
         return '2017-03-21T13:00:00.000Z'
diff --git a/tests/configuration/test_network.py b/tests/configuration/test_network.py
index 5ac1654..a7080f1 100644
--- a/tests/configuration/test_network.py
+++ b/tests/configuration/test_network.py
@@ -17,20 +17,20 @@ def chain_id(self):
 
 def test_get_network():
     result = Network.get_network()
-    assert result.chain_id() == 10000
+    assert result.chain_id() == 11812
 
 def test_set_network():
     # mainnet
     Network.set_network(Mainnet())
     result = Network.get_network()
     assert result.wif() == 'ba'
-    assert result.chain_id() == 10000
+    assert result.chain_id() == 11811
 
     # testnet
     Network.set_network(Testnet())
     result = Network.get_network()
     assert result.wif() == 'ba'
-    assert result.chain_id() == 10000
+    assert result.chain_id() == 11812
 
     Network.set_network(Testnet())  # set back to Testnet so other tests don't fail