diff --git a/PC/VS9.0/_elementtree.vcproj b/PC/VS9.0/_elementtree.vcproj
index 5e799557679fd8a..f89409cc3ed1497 100644
--- a/PC/VS9.0/_elementtree.vcproj
+++ b/PC/VS9.0/_elementtree.vcproj
@@ -105,7 +105,7 @@
 			<Tool
 				Name="VCCLCompilerTool"
 				AdditionalIncludeDirectories="..\..\Modules\expat"
-				PreprocessorDefinitions="USE_PYEXPAT_CAPI;XML_STATIC"
+				PreprocessorDefinitions="_CRT_SECURE_NO_WARNINGS;USE_PYEXPAT_CAPI;XML_STATIC"
 			/>
 			<Tool
 				Name="VCManagedResourceCompilerTool"
diff --git a/PC/VS9.0/pyexpat.vcproj b/PC/VS9.0/pyexpat.vcproj
index 32ec10dd7a8ec27..76b698f74028a5c 100644
--- a/PC/VS9.0/pyexpat.vcproj
+++ b/PC/VS9.0/pyexpat.vcproj
@@ -43,7 +43,7 @@
 			<Tool
 				Name="VCCLCompilerTool"
 				AdditionalIncludeDirectories=".\..\..\Modules\expat"
-				PreprocessorDefinitions="PYEXPAT_EXPORTS;XML_STATIC"
+				PreprocessorDefinitions="_CRT_SECURE_NO_WARNINGS;PYEXPAT_EXPORTS;XML_STATIC"
 			/>
 			<Tool
 				Name="VCManagedResourceCompilerTool"
diff --git a/PCbuild/_elementtree.vcxproj b/PCbuild/_elementtree.vcxproj
index 3a271ef593121e5..511e26bb60dbd86 100644
--- a/PCbuild/_elementtree.vcxproj
+++ b/PCbuild/_elementtree.vcxproj
@@ -62,7 +62,7 @@
   <ItemDefinitionGroup>
     <ClCompile>
       <AdditionalIncludeDirectories>..\Modules\expat;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
-      <PreprocessorDefinitions>USE_PYEXPAT_CAPI;XML_STATIC;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <PreprocessorDefinitions>_CRT_SECURE_NO_WARNINGS;USE_PYEXPAT_CAPI;XML_STATIC;%(PreprocessorDefinitions)</PreprocessorDefinitions>
     </ClCompile>
     <Link>
       <BaseAddress>0x1D100000</BaseAddress>
diff --git a/PCbuild/pyexpat.vcxproj b/PCbuild/pyexpat.vcxproj
index 6d036d13dab9086..61a2697e1166307 100644
--- a/PCbuild/pyexpat.vcxproj
+++ b/PCbuild/pyexpat.vcxproj
@@ -59,7 +59,7 @@
   <ItemDefinitionGroup>
     <ClCompile>
       <AdditionalIncludeDirectories>$(PySourcePath)Modules\expat;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
-      <PreprocessorDefinitions>PYEXPAT_EXPORTS;XML_STATIC;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <PreprocessorDefinitions>_CRT_SECURE_NO_WARNINGS;PYEXPAT_EXPORTS;XML_STATIC;%(PreprocessorDefinitions)</PreprocessorDefinitions>
     </ClCompile>
   </ItemDefinitionGroup>
   <ItemGroup>