diff --git a/PCbuild/pythoncore.vcxproj b/PCbuild/pythoncore.vcxproj
index c39ba3e1a9f412..3ba63587642d1a 100644
--- a/PCbuild/pythoncore.vcxproj
+++ b/PCbuild/pythoncore.vcxproj
@@ -499,7 +499,9 @@
     <ClCompile Include="$(zlibDir)\adler32.c" />
     <ClCompile Include="$(zlibDir)\compress.c" />
     <ClCompile Include="$(zlibDir)\crc32.c" />
-    <ClCompile Include="$(zlibDir)\deflate.c" />
+    <ClCompile Include="$(zlibDir)\deflate.c">
+      <DisableSpecificWarnings>4244</DisableSpecificWarnings>
+    </ClCompile>
     <ClCompile Include="$(zlibDir)\infback.c" />
     <ClCompile Include="$(zlibDir)\inffast.c" />
     <ClCompile Include="$(zlibDir)\inflate.c" />