diff --git a/include/FLAC++/metadata.h b/include/FLAC++/metadata.h
index 08b15b0e..2839d3b4 100644
--- a/include/FLAC++/metadata.h
+++ b/include/FLAC++/metadata.h
@@ -215,6 +215,11 @@ namespace FLAC {
 			inline void set_reference(bool x) { is_reference_ = x; }
 		};
 
+#ifdef _MSC_VER
+// warning C4800: 'int' : forcing to bool 'true' or 'false' (performance warning)
+#pragma warning ( disable : 4800 )
+#endif
+
 		inline bool Prototype::operator==(const Prototype &object) const
 		{ return (bool)::FLAC__metadata_object_is_equal(object_, object.object_); }
 
@@ -224,6 +229,11 @@ namespace FLAC {
 		inline bool Prototype::operator==(const ::FLAC__StreamMetadata *object) const
 		{ return (bool)::FLAC__metadata_object_is_equal(object_, object); }
 
+#ifdef _MSC_VER
+// @@@ how to re-enable?  the following doesn't work
+// #pragma warning ( enable : 4800 )
+#endif
+
 		inline bool Prototype::operator!=(const Prototype &object) const
 		{ return !operator==(object); }
 
diff --git a/src/libFLAC++/metadata.cpp b/src/libFLAC++/metadata.cpp
index fd6e763e..ba0e0d30 100644
--- a/src/libFLAC++/metadata.cpp
+++ b/src/libFLAC++/metadata.cpp
@@ -34,6 +34,11 @@
 #include <stdlib.h> // for malloc(), free()
 #include <string.h> // for memcpy() etc.
 
+#ifdef _MSC_VER
+// warning C4800: 'int' : forcing to bool 'true' or 'false' (performance warning)
+#pragma warning ( disable : 4800 )
+#endif
+
 namespace FLAC {
 	namespace Metadata {
 
diff --git a/src/test_libFLAC++/decoders.cpp b/src/test_libFLAC++/decoders.cpp
index d44d34dd..06453c2a 100644
--- a/src/test_libFLAC++/decoders.cpp
+++ b/src/test_libFLAC++/decoders.cpp
@@ -30,6 +30,11 @@ extern "C" {
 #include <stdlib.h>
 #include <string.h>
 
+#ifdef _MSC_VER
+// warning C4800: 'int' : forcing to bool 'true' or 'false' (performance warning)
+#pragma warning ( disable : 4800 )
+#endif
+
 static ::FLAC__StreamMetadata streaminfo_, padding_, seektable_, application1_, application2_, vorbiscomment_, cuesheet_, unknown_;
 static ::FLAC__StreamMetadata *expected_metadata_sequence_[8];
 static unsigned num_expected_;
diff --git a/src/test_libOggFLAC++/decoders.cpp b/src/test_libOggFLAC++/decoders.cpp
index 874515b6..9d89a2a4 100644
--- a/src/test_libOggFLAC++/decoders.cpp
+++ b/src/test_libOggFLAC++/decoders.cpp
@@ -30,6 +30,11 @@ extern "C" {
 #include <stdlib.h>
 #include <string.h>
 
+#ifdef _MSC_VER
+// warning C4800: 'int' : forcing to bool 'true' or 'false' (performance warning)
+#pragma warning ( disable : 4800 )
+#endif
+
 static ::FLAC__StreamMetadata streaminfo_, padding_, seektable_, application1_, application2_, vorbiscomment_, cuesheet_, unknown_;
 static ::FLAC__StreamMetadata *expected_metadata_sequence_[8];
 static unsigned num_expected_;