diff --git a/arch-nspawn.in b/arch-nspawn.in
index 6900382..343075d 100644
--- a/arch-nspawn.in
+++ b/arch-nspawn.in
@@ -76,7 +76,10 @@ copy_hostconf () {
 	[[ -n $pac_conf ]] && cp $pac_conf "$working_dir/etc/pacman.conf"
 	[[ -n $makepkg_conf ]] && cp $makepkg_conf "$working_dir/etc/makepkg.conf"
 
-	sed -r "s|^#?\\s*CacheDir.+|CacheDir = $(echo -n ${cache_dirs[@]})|g" -i "$working_dir/etc/pacman.conf"
+	chroot_cache_dirs=($(sed '/^\s*CacheDir/!d;s/^\s*CacheDir\s*=\s*//g;s/\s//g' "$working_dir/etc/pacman.conf"))
+	if [ "${cache_dirs[@]}" != "/var/cache/pacman/pkg/" -a "${chroot_cache_dirs[@]}" == "/var/cache/pacman/pkg/" ]; then
+		sed -r "s|^#?\\s*CacheDir.+|CacheDir = $(echo -n ${cache_dirs[@]})|g" -i "$working_dir/etc/pacman.conf"
+	fi
 }
 # }}}