diff --git a/sync_build_test.sh b/sync_build_test.sh
index ce19479e92..4fb27151a5 100755
--- a/sync_build_test.sh
+++ b/sync_build_test.sh
@@ -52,6 +52,9 @@ DEFINE_boolean build ${FLAGS_TRUE} \
 DEFINE_boolean build_autotest ${FLAGS_FALSE} "Build autotest"
 DEFINE_string buildbot_uri "${BUILDBOT_URI}" \
     "Base URI to buildbot build location which contains LATEST file"
+DEFINE_string chrome_root "" \
+    "The root of your chrome browser source. Should contain a 'src' subdir. \
+If this is set, chrome browser will be built from source."
 DEFINE_string chronos_passwd "${CHRONOS_PASSWD}" \
     "Use this as the chronos user passwd (defaults to \$CHRONOS_PASSWD)"
 DEFINE_string chroot "" "Chroot to build/use"
@@ -82,7 +85,6 @@ DEFINE_boolean withdev ${FLAGS_TRUE} "Build development packages"
 DEFINE_boolean usepkg ${FLAGS_TRUE} "Use binary packages"
 DEFINE_boolean unittest ${FLAGS_TRUE} "Run unit tests"
 
-
 # Returns a heuristic indicating if we believe this to be a google internal
 # development environment.
 # Returns:
@@ -126,6 +128,11 @@ function validate_and_set_param_defaults() {
     FLAGS_force_make_chroot=${FLAGS_TRUE}
   fi
 
+  # If chrome_root option passed, set as option for ./enter_chroot
+  if [[ -n "${FLAGS_chrome_root}" ]]; then
+    chroot_options="--chrome_root=${FLAGS_chrome_root}"
+  fi
+
   if [[ -z "${FLAGS_repo}" ]]; then
     if is_google_environment; then
       FLAGS_repo="ssh://git@chromiumos-git//chromeos"
@@ -360,7 +367,8 @@ function run_phase() {
 function run_phase_in_chroot() {
   local desc="$1"
   shift
-  run_phase "${desc}" ./enter_chroot.sh "--chroot=${FLAGS_chroot}" -- "$@"
+  run_phase "${desc}" ./enter_chroot.sh "--chroot=${FLAGS_chroot}" \
+    ${chroot_options} -- "$@"
 }
 
 
@@ -533,6 +541,12 @@ function main() {
     fi
   fi
 
+  if [[ ${FLAGS_chrome_root} ]]; then
+      run_phase_in_chroot "Building Chromium browser" \
+        USE="build_tests" FEATURES="-usersandbox" \
+        CHROME_ORIGIN=LOCAL_SOURCE emerge-${FLAGS_board} chromeos-chrome
+  fi
+
   if [[ ${FLAGS_master} -eq ${FLAGS_TRUE} ]]; then
     chdir_relative src/scripts
     if [[ -n "${FLAGS_chronos_passwd}" ]]; then