diff --git a/jmclient/jmclient/blockchaininterface.py b/jmclient/jmclient/blockchaininterface.py
index cab1fbf..0d6c320 100644
--- a/jmclient/jmclient/blockchaininterface.py
+++ b/jmclient/jmclient/blockchaininterface.py
@@ -842,12 +842,12 @@ class BitcoinCoreInterface(BlockchainInterface):
     def estimate_fee_per_kb(self, N):
         if super(BitcoinCoreInterface, self).fee_per_kb_has_been_manually_set(N):
             return int(random.uniform(N * float(0.8), N * float(1.2)))
-        estimate = int(Decimal(1e8) * Decimal(self.rpc('estimatefee', [N])))
+        estimate = int(Decimal(1e8) * Decimal(self.rpc('estimatesmartfee', [N])['feerate']))
         if (N == 1) and (estimate < 0):
             # Special bitcoin core case: sometimes the highest priority
             # cannot be estimated in that case the 2nd highest priority
             # should be used instead of falling back to hardcoded values
-            estimate = int(Decimal(1e8) * Decimal(self.rpc('estimatefee', [N+1])))
+            estimate = int(Decimal(1e8) * Decimal(self.rpc('estimatesmartfee', [N+1])['feerate']))
         if estimate < 0:
             # This occurs when Core has insufficient data to estimate.
             return 100000