diff --git a/src/source.cpp b/src/source.cpp
--- a/src/source.cpp
+++ b/src/source.cpp
@@ -1,5 +1,5 @@
 /*
-  Copyright © 2017 Hasan Yavuz Özderya
+  Copyright © 2018 Hasan Yavuz Özderya
 
   This file is part of serialplot.
 
@@ -21,6 +21,14 @@
 
 #include "source.h"
 
+Source::~Source()
+{
+    for (auto sink : sinks)
+    {
+        sink->setSource(NULL);
+    }
+}
+
 void Source::connect(Sink* sink)
 {
     Q_ASSERT(!sinks.contains(sink));