diff --git a/taglib/ape/apeitem.cpp b/taglib/ape/apeitem.cpp
index 3490173a..49c3a665 100644
--- a/taglib/ape/apeitem.cpp
+++ b/taglib/ape/apeitem.cpp
@@ -86,8 +86,10 @@ APE::Item::~Item()
 
 Item &APE::Item::operator=(const Item &item)
 {
-  delete d;
-  d = new ItemPrivate(*item.d);
+  if(&item != this) {
+    delete d;
+    d = new ItemPrivate(*item.d);
+  }
   return *this;
 }
 
diff --git a/taglib/asf/asfattribute.cpp b/taglib/asf/asfattribute.cpp
index 116bfe21..7a40bea3 100644
--- a/taglib/asf/asfattribute.cpp
+++ b/taglib/asf/asfattribute.cpp
@@ -72,10 +72,12 @@ ASF::Attribute::Attribute(const ASF::Attribute &other)
 
 ASF::Attribute &ASF::Attribute::operator=(const ASF::Attribute &other)
 {
-  if(d->deref())
-    delete d;
-  d = other.d;
-  d->ref();
+  if(&other != this) {
+    if(d->deref())
+      delete d;
+    d = other.d;
+    d->ref();
+  }
   return *this;
 }
 
diff --git a/taglib/mp4/mp4coverart.cpp b/taglib/mp4/mp4coverart.cpp
index 2746469d..f2152335 100644
--- a/taglib/mp4/mp4coverart.cpp
+++ b/taglib/mp4/mp4coverart.cpp
@@ -54,11 +54,12 @@ MP4::CoverArt::CoverArt(const CoverArt &item) : d(item.d)
 MP4::CoverArt &
 MP4::CoverArt::operator=(const CoverArt &item)
 {
-  if(d->deref()) {
-    delete d;
+  if(&item != this) {
+    if(d->deref())
+      delete d;
+    d = item.d;
+    d->ref();
   }
-  d = item.d;
-  d->ref();
   return *this;
 }
 
diff --git a/taglib/mp4/mp4item.cpp b/taglib/mp4/mp4item.cpp
index 671f26b4..aa59feda 100644
--- a/taglib/mp4/mp4item.cpp
+++ b/taglib/mp4/mp4item.cpp
@@ -64,11 +64,13 @@ MP4::Item::Item(const Item &item) : d(item.d)
 MP4::Item &
 MP4::Item::operator=(const Item &item)
 {
-  if(d->deref()) {
-    delete d;
+  if(&item != this) {
+    if(d->deref()) {
+      delete d;
+    }
+    d = item.d;
+    d->ref();
   }
-  d = item.d;
-  d->ref();
   return *this;
 }