diff --git a/source/org/jivesoftware/smack/PacketReader.java b/source/org/jivesoftware/smack/PacketReader.java
index afab76779..93c7be5a9 100644
--- a/source/org/jivesoftware/smack/PacketReader.java
+++ b/source/org/jivesoftware/smack/PacketReader.java
@@ -154,7 +154,9 @@ class PacketReader {
                             break;
                         }
                         connectionIDLock.wait(waitTime);
-                        waitTime -= System.currentTimeMillis() - start;
+                        long now = System.currentTimeMillis();
+                        waitTime -= now - start;
+                        start = now;
                     }
                 }
             }
diff --git a/source/org/jivesoftware/smack/XMPPConnection.java b/source/org/jivesoftware/smack/XMPPConnection.java
index 7cf19b8fd..3ee9f1656 100644
--- a/source/org/jivesoftware/smack/XMPPConnection.java
+++ b/source/org/jivesoftware/smack/XMPPConnection.java
@@ -459,7 +459,9 @@ public class XMPPConnection {
                             break;
                         }
                         roster.wait(waitTime);
-                        waitTime -= System.currentTimeMillis() - start;
+                        long now = System.currentTimeMillis();
+                        waitTime -= now - start;
+                        start = now;
                     }
                 }
             }