diff --git a/lib/services/bitcoind.js b/lib/services/bitcoind.js
index 216c72ae..c9dbf4e8 100644
--- a/lib/services/bitcoind.js
+++ b/lib/services/bitcoind.js
@@ -70,6 +70,7 @@ Bitcoin.prototype._initCaches = function() {
   this.rawBlockCache = LRU(72);
   this.blockHeaderCache = LRU(288);
   this.zmqKnownTransactions = LRU(50);
+  this.zmqKnownBlocks = LRU(50);
   this.zmqLastBlock = 0;
   this.zmqUpdateTipTimeout = false;
 };
@@ -322,7 +323,7 @@ Bitcoin.prototype._zmqBlockHandler = function(node, message) {
     }
   }
 
-  // Prevent a rapid succession of updates
+  // Prevent a rapid succession of tip updates
   if (new Date() - self.zmqLastBlock > 1000) {
     self.zmqLastBlock = new Date();
     updateChain();
@@ -334,8 +335,15 @@ Bitcoin.prototype._zmqBlockHandler = function(node, message) {
   }
 
   // Notify block subscribers
-  for (var i = 0; i < this.subscriptions.block.length; i++) {
-    this.subscriptions.block[i].emit('bitcoind/block', message.toString('hex'));
+  var id = message.toString('binary');
+  if (!self.zmqKnownBlocks[id]) {
+    self.zmqKnownBlocks[id] = true;
+    self.emit('block', message);
+
+    for (var i = 0; i < this.subscriptions.block.length; i++) {
+      this.subscriptions.block[i].emit('bitcoind/block', message.toString('hex'));
+    }
+
   }
 
 };