diff --git a/gfx/src/beos/nsDeviceContextBeOS.cpp b/gfx/src/beos/nsDeviceContextBeOS.cpp
index bd795816e859..ccb91441a4af 100644
--- a/gfx/src/beos/nsDeviceContextBeOS.cpp
+++ b/gfx/src/beos/nsDeviceContextBeOS.cpp
@@ -61,8 +61,6 @@ static NS_DEFINE_CID(kPrefCID, NS_PREF_CID);
  
 nscoord nsDeviceContextBeOS::mDpi = 96; 
  
-NS_IMPL_ISUPPORTS1(nsDeviceContextBeOS, nsIDeviceContext) 
- 
 nsDeviceContextBeOS::nsDeviceContextBeOS()
 {
   NS_INIT_REFCNT();
diff --git a/gfx/src/beos/nsDeviceContextBeOS.h b/gfx/src/beos/nsDeviceContextBeOS.h
index 7ec54668c548..8145603479f5 100644
--- a/gfx/src/beos/nsDeviceContextBeOS.h
+++ b/gfx/src/beos/nsDeviceContextBeOS.h
@@ -53,8 +53,6 @@ public:
   nsDeviceContextBeOS();
   virtual ~nsDeviceContextBeOS();
 
-  NS_DECL_ISUPPORTS
-
   NS_IMETHOD  Init(nsNativeWidget aNativeWidget);
 
   NS_IMETHOD  CreateRenderingContext(nsIRenderingContext *&aContext);
diff --git a/gfx/src/photon/nsDeviceContextPh.cpp b/gfx/src/photon/nsDeviceContextPh.cpp
index 38fec9f4ad6e..28e7d70af8bd 100644
--- a/gfx/src/photon/nsDeviceContextPh.cpp
+++ b/gfx/src/photon/nsDeviceContextPh.cpp
@@ -93,8 +93,6 @@ nsDeviceContextPh :: ~nsDeviceContextPh( ) {
 	NS_IF_RELEASE( mSpec );
 	}
 
-NS_IMPL_ISUPPORTS1(nsDeviceContextPh, nsIDeviceContext)
-
 NS_IMETHODIMP nsDeviceContextPh :: Init( nsNativeWidget aWidget ) {
   float newscale, origscale;
   float a2d,t2d;
diff --git a/gfx/src/photon/nsDeviceContextPh.h b/gfx/src/photon/nsDeviceContextPh.h
index 5336cbbcba15..1cd7c907241d 100644
--- a/gfx/src/photon/nsDeviceContextPh.h
+++ b/gfx/src/photon/nsDeviceContextPh.h
@@ -55,8 +55,6 @@ public:
   nsDeviceContextPh();
   virtual ~nsDeviceContextPh();
   
-  NS_DECL_ISUPPORTS
-  
   NS_IMETHOD  Init(nsNativeWidget aWidget);
 
 
diff --git a/gfx/src/qt/nsDeviceContextQT.cpp b/gfx/src/qt/nsDeviceContextQT.cpp
index 2f1638f9d876..d295c07b1aab 100644
--- a/gfx/src/qt/nsDeviceContextQT.cpp
+++ b/gfx/src/qt/nsDeviceContextQT.cpp
@@ -68,8 +68,6 @@ static NS_DEFINE_CID(kPrefCID,NS_PREF_CID);
 
 nscoord nsDeviceContextQT::mDpi = 96;
 
-NS_IMPL_ISUPPORTS1(nsDeviceContextQT,nsIDeviceContext)
-
 nsDeviceContextQT::nsDeviceContextQT()
 {
   NS_INIT_REFCNT();
diff --git a/gfx/src/qt/nsDeviceContextQT.h b/gfx/src/qt/nsDeviceContextQT.h
index dbb2832f68f8..1d7ba4a5bf53 100644
--- a/gfx/src/qt/nsDeviceContextQT.h
+++ b/gfx/src/qt/nsDeviceContextQT.h
@@ -53,8 +53,6 @@ public:
     nsDeviceContextQT();
     virtual ~nsDeviceContextQT();
 
-    NS_DECL_ISUPPORTS
-
     NS_IMETHOD  Init(nsNativeWidget aNativeWidget);
 
     NS_IMETHOD  CreateRenderingContext(nsIRenderingContext *&aContext);