diff --git a/include/boost/function.hpp b/include/boost/function.hpp
index cd63901..4bacd2f 100644
--- a/include/boost/function.hpp
+++ b/include/boost/function.hpp
@@ -462,6 +462,9 @@ namespace boost {
                                                                             
     function& operator=(const function& f)                                  
     {   
+      if (this == &f)
+        return *this;
+
       const base_type& bf = static_cast<const base_type&>(f);
       base_type* self = this;
       self->set(bf);
@@ -470,6 +473,9 @@ namespace boost {
 
     void set(const function& f)                             
     {
+      if (this == &f)
+        return;
+
       const base_type& bf = static_cast<const base_type&>(f);
       base_type* self = this;
       self->set(bf);
diff --git a/include/boost/function/function_template.hpp b/include/boost/function/function_template.hpp
index b8532de..8e70487 100644
--- a/include/boost/function/function_template.hpp
+++ b/include/boost/function/function_template.hpp
@@ -1044,6 +1044,9 @@ namespace boost {
     // Assignment from another BOOST_FUNCTION_FUNCTION
     BOOST_FUNCTION_FUNCTION& operator=(const BOOST_FUNCTION_FUNCTION& f)
     {
+      if (this == &f)
+        return *this;
+
       clear();
 
       if (!f.empty()) {
@@ -1064,6 +1067,9 @@ namespace boost {
     // Assignment from another BOOST_FUNCTION_FUNCTION
     void set(const BOOST_FUNCTION_FUNCTION& f)
     {
+      if (this == &f)
+        return;
+
       clear();
 
       if (!f.empty()) {
@@ -1624,6 +1630,9 @@ namespace boost {
     // Assignment from another BOOST_FUNCTION_FUNCTION
     BOOST_FUNCTION_FUNCTION& operator=(const BOOST_FUNCTION_FUNCTION& f)
     {
+      if (this == &f)
+        return *this;
+
       clear();
 
       if (!f.empty()) {
@@ -1644,6 +1653,9 @@ namespace boost {
     // Assignment from another BOOST_FUNCTION_FUNCTION
     void set(const BOOST_FUNCTION_FUNCTION& f)
     {
+      if (this == &f)
+        return;
+
       clear();
 
       if (!f.empty()) {