diff --git a/.gitignore b/.gitignore
index e41ec8cbd6..75afb30235 100644
--- a/.gitignore
+++ b/.gitignore
@@ -7,7 +7,9 @@
 /.versions
 
 # ignore ninja.exe copied from .cipd_bin.
-/ninja.exe
+# TODO(crbug.com/931218): checkin ninja.exe for issues that can't ensure
+# ninja.exe as expected.
+# /ninja.exe
 
 # Ignore "disable auto update" sentinel file.
 .disable_auto_update
diff --git a/cipd_bin_setup.bat b/cipd_bin_setup.bat
index 3936fc0d53..8ace8869df 100644
--- a/cipd_bin_setup.bat
+++ b/cipd_bin_setup.bat
@@ -5,4 +5,5 @@
 
 call "%~dp0\cipd.bat" ensure -log-level warning -ensure-file "%~dp0\cipd_manifest.txt" -root "%~dp0\.cipd_bin"
 :: copy ninja.exe to the root since many places assume ninja.exe exists in depot_tools.
-copy /y "%~dp0\.cipd_bin\ninja.exe" "%~dp0\ninja.exe" > nul
+:: TODO(crbug.com/931218): check in ninja.exe for now.
+:: copy /y "%~dp0\.cipd_bin\ninja.exe" "%~dp0\ninja.exe" > nul
diff --git a/ninja.exe b/ninja.exe
new file mode 100644
index 0000000000..799949ed68
Binary files /dev/null and b/ninja.exe differ