diff --git a/gfx/src/thebes/nsThebesFontEnumerator.cpp b/gfx/src/thebes/nsThebesFontEnumerator.cpp
index bcaf8c8502aa..d6cc492a05a4 100644
--- a/gfx/src/thebes/nsThebesFontEnumerator.cpp
+++ b/gfx/src/thebes/nsThebesFontEnumerator.cpp
@@ -124,7 +124,7 @@ nsThebesFontEnumerator::GetDefaultFont(const char *aLangGroup,
 NS_IMETHODIMP
 nsThebesFontEnumerator::UpdateFontList(PRBool *_retval)
 {
-    nsresult rv = gfxPlatform::GetPlatform()->UpdateFontList();
+    gfxPlatform::GetPlatform()->UpdateFontList();
     *_retval = PR_FALSE; // always return false for now
     return NS_OK;
 }
diff --git a/gfx/src/thebes/nsThebesRenderingContext.cpp b/gfx/src/thebes/nsThebesRenderingContext.cpp
index 33b1723e2c75..28eac5509444 100644
--- a/gfx/src/thebes/nsThebesRenderingContext.cpp
+++ b/gfx/src/thebes/nsThebesRenderingContext.cpp
@@ -98,8 +98,6 @@ nsThebesRenderingContext::Init(nsIDeviceContext* aContext, gfxASurface *aThebesS
 {
     PR_LOG(gThebesGFXLog, PR_LOG_DEBUG, ("## %p nsTRC::Init ctx %p thebesSurface %p\n", this, aContext, aThebesSurface));
 
-    nsThebesDeviceContext *thebesDC = static_cast<nsThebesDeviceContext*>(aContext);
-
     mDeviceContext = aContext;
     mWidget = nsnull;
 
@@ -126,8 +124,6 @@ nsThebesRenderingContext::Init(nsIDeviceContext* aContext, nsIWidget *aWidget)
 {
     PR_LOG(gThebesGFXLog, PR_LOG_DEBUG, ("## %p nsTRC::Init ctx %p widget %p\n", this, aContext, aWidget));
 
-    nsThebesDeviceContext *thebesDC = static_cast<nsThebesDeviceContext*>(aContext);
-
     mDeviceContext = aContext;
     mWidget = aWidget;
 
diff --git a/gfx/thebes/src/gfxFont.cpp b/gfx/thebes/src/gfxFont.cpp
index 710c70b360cc..4cf8d59a9080 100644
--- a/gfx/thebes/src/gfxFont.cpp
+++ b/gfx/thebes/src/gfxFont.cpp
@@ -2328,9 +2328,9 @@ gfxTextRun::CopyGlyphDataFrom(gfxTextRun *aSource, PRUint32 aStart,
         NS_ASSERTION(font != lastFont, "Glyphruns not coalesced?");
 #ifdef DEBUG
         lastFont = font;
+        PRUint32 end = iter.GetStringEnd();
 #endif
         PRUint32 start = iter.GetStringStart();
-        PRUint32 end = iter.GetStringEnd();
         NS_ASSERTION(aSource->IsClusterStart(start),
                      "Started word in the middle of a cluster...");
         NS_ASSERTION(end == aSource->GetLength() || aSource->IsClusterStart(end),
diff --git a/gfx/thebes/src/gfxFontUtils.cpp b/gfx/thebes/src/gfxFontUtils.cpp
index f43129f91679..a67c691c03b9 100644
--- a/gfx/thebes/src/gfxFontUtils.cpp
+++ b/gfx/thebes/src/gfxFontUtils.cpp
@@ -295,7 +295,7 @@ gfxFontUtils::ReadCMAPTableFormat4(PRUint8 *aBuf, PRInt32 aLength, gfxSparseBitS
         if (idRangeOffset == 0) {
             aCharacterMap.SetRange(startCount, endCount);
         } else {
-            const PRUint16 idDelta = ReadShortAt16(idDeltas, i);
+            // const PRUint16 idDelta = ReadShortAt16(idDeltas, i); // Unused: self-documenting.
             for (PRUint32 c = startCount; c <= endCount; ++c) {
                 if (c == 0xFFFF)
                     break;
@@ -366,7 +366,7 @@ gfxFontUtils::ReadCMAP(PRUint8 *aBuf, PRUint32 aBufLength, gfxSparseBitSet& aCha
         EncodingIDUCS4ForMicrosoftPlatform = 10
     };
 
-    PRUint16 version = ReadShortAt(aBuf, OffsetVersion);
+    // PRUint16 version = ReadShortAt(aBuf, OffsetVersion); // Unused: self-documenting.
     PRUint16 numTables = ReadShortAt(aBuf, OffsetNumTables);
 
     // save the format and offset we want here
diff --git a/gfx/thebes/src/gfxPangoFonts.cpp b/gfx/thebes/src/gfxPangoFonts.cpp
index f64bf69c1baa..8f0eb7e4c1ad 100644
--- a/gfx/thebes/src/gfxPangoFonts.cpp
+++ b/gfx/thebes/src/gfxPangoFonts.cpp
@@ -1643,7 +1643,9 @@ gfxPangoFontGroup::CreateGlyphRunsItemizing(gfxTextRun *aTextRun,
     GList *items = pango_itemize_with_base_dir(context, dir, aUTF8, 0, aUTF8Length, nsnull, nsnull);
 
     PRUint32 utf16Offset = 0;
+#ifdef DEBUG
     PRBool isRTL = aTextRun->IsRightToLeft();
+#endif
     GList *pos = items;
     PangoGlyphString *glyphString = pango_glyph_string_new();
     if (!glyphString)