diff --git a/classes/Leth/IPAddress/IP/NetworkAddress.php b/classes/Leth/IPAddress/IP/NetworkAddress.php
index ea8f959..a85a466 100755
--- a/classes/Leth/IPAddress/IP/NetworkAddress.php
+++ b/classes/Leth/IPAddress/IP/NetworkAddress.php
@@ -187,7 +187,7 @@ abstract class NetworkAddress implements \IteratorAggregate, \Countable
 						$last_added = $a;
 					}
 				}
-				if ($last_added !== $b && $last_added->compare_to($b) !== 0)
+				if (!$last_added || ($last_added !== $b && $last_added->compare_to($b) !== 0))
 					$out[] = $b;
 				// We're done with these, remove them to allow GC
 				unset($cidr_addrs[$cidr]);
diff --git a/tests/IPNetworkAddressTest.php b/tests/IPNetworkAddressTest.php
index 09df6dd..37cb984 100644
--- a/tests/IPNetworkAddressTest.php
+++ b/tests/IPNetworkAddressTest.php
@@ -491,6 +491,11 @@ class IP_NetworkAddress_Test extends PHPUnit_Framework_TestCase
 				array('0.0.0.0/32', '0.0.0.1/32', '::0/128', '::1/128'),
 				array('0.0.0.0/31', '::0/127'),
 			),
+			// Merge with duplicate resultant entry
+			array(
+				array('0.0.0.0/22', '0.0.0.0/24', '0.0.1.0/24', '0.0.2.0/24', '0.0.3.0/24'),
+				array('0.0.0.0/22'),
+			),
 		);
 
 		foreach ($data as &$x)