diff --git a/src/conversions.cpp b/src/conversions.cpp
index f1534dd9..c986f57b 100644
--- a/src/conversions.cpp
+++ b/src/conversions.cpp
@@ -13,8 +13,6 @@
 // 04 Mar 01  std::complex<> fixes for MSVC (Dave Abrahams)
 // 03 Mar 01  added: converters for [plain] char (Ralf W. Grosse-Kunstleve)
 
-#define BOOST_PYTHON_SOURCE
-
 #include <boost/python/conversions.hpp>
 #include <boost/python/detail/void_adaptor.hpp>
 #include <typeinfo>
diff --git a/src/cross_module.cpp b/src/cross_module.cpp
index 5949be4d..ea5a08de 100644
--- a/src/cross_module.cpp
+++ b/src/cross_module.cpp
@@ -8,8 +8,6 @@
      17 Apr 01 merged into boost CVS trunk (Ralf W. Grosse-Kunstleve)
 */
 
-#define BOOST_PYTHON_SOURCE
-
 # include <boost/python/cross_module.hpp>
 namespace python = boost::python;
 # include <stdio.h> // MSVC6.0SP4 does not know std::fprintf
diff --git a/src/extension_class.cpp b/src/extension_class.cpp
index e9183c82..3815a19c 100644
--- a/src/extension_class.cpp
+++ b/src/extension_class.cpp
@@ -9,8 +9,6 @@
 // Revision History:
 // 04 Mar 01  Use PyObject_INIT() instead of trying to hand-initialize (David Abrahams)
 
-#define BOOST_PYTHON_SOURCE
-
 #include <boost/python/detail/extension_class.hpp>
 #include <boost/utility.hpp>
 #include <boost/bind.hpp>
diff --git a/src/functions.cpp b/src/functions.cpp
index ecbacf4e..a04e2e51 100644
--- a/src/functions.cpp
+++ b/src/functions.cpp
@@ -9,8 +9,6 @@
 // Revision History:
 // Mar 01 01  Use PyObject_INIT() instead of trying to hand-initialize (David Abrahams)
 
-#define BOOST_PYTHON_SOURCE
-
 #include <boost/python/detail/functions.hpp>
 #include <boost/python/detail/types.hpp>
 #include <boost/python/detail/singleton.hpp>
diff --git a/src/init_function.cpp b/src/init_function.cpp
index 1ebfa501..1667724c 100644
--- a/src/init_function.cpp
+++ b/src/init_function.cpp
@@ -6,8 +6,6 @@
 //  The author gratefully acknowleges the support of Dragon Systems, Inc., in
 //  producing this work.
 
-#define BOOST_PYTHON_SOURCE
-
 #include <boost/python/detail/init_function.hpp>
 #include <boost/python/objects.hpp>
 #include <boost/python/detail/extension_class.hpp>
diff --git a/src/module_builder.cpp b/src/module_builder.cpp
index bd04a89c..57eec75f 100644
--- a/src/module_builder.cpp
+++ b/src/module_builder.cpp
@@ -6,8 +6,6 @@
 //  The author gratefully acknowleges the support of Dragon Systems, Inc., in
 //  producing this work.
 
-#define BOOST_PYTHON_SOURCE
-
 #include <boost/python/module_builder.hpp>
 
 namespace boost { namespace python {
diff --git a/src/objects.cpp b/src/objects.cpp
index 70257388..125a1eb8 100644
--- a/src/objects.cpp
+++ b/src/objects.cpp
@@ -8,8 +8,6 @@
 
 // TODO: Move inline implementations from objects.cpp here
 
-#define BOOST_PYTHON_SOURCE
-
 #include <boost/python/objects.hpp>
 #include <boost/python/detail/none.hpp>
 
diff --git a/src/types.cpp b/src/types.cpp
index f411aa42..c7e1f167 100644
--- a/src/types.cpp
+++ b/src/types.cpp
@@ -6,8 +6,6 @@
 //  The author gratefully acknowleges the support of Dragon Systems, Inc., in
 //  producing this work.
 
-#define BOOST_PYTHON_SOURCE
-
 #include <boost/python/detail/types.hpp>
 #include <boost/python/reference.hpp> // for handle_exception()
 #include <boost/python/conversions.hpp>