diff --git a/net/instaweb/rewriter/css_inline_filter.cc b/net/instaweb/rewriter/css_inline_filter.cc
index 9e37e18..243a474 100644
--- a/net/instaweb/rewriter/css_inline_filter.cc
+++ b/net/instaweb/rewriter/css_inline_filter.cc
@@ -117,6 +117,16 @@
   const char* media = NULL;
   if (CssTagScanner::ParseCssElement(element, &href, &media) &&
       !driver()->HasChildrenInFlushWindow(element)) {
+    if (driver()->is_amp_document()) {
+      // Don't inline into AMP documents. Those do permit font loading CSS,
+      // which we could in principle inline, but they also restrict the document
+      // to a single <style> tag, and we don't really have a good way of
+      // coordinating everything into that.
+      driver()->InsertDebugComment(
+          "CSS inlining not supported by PageSpeed for AMP documents", element);
+      return;
+    }
+
     // Only inline if the media type affects "screen".  We don't inline other
     // types since they're very unlikely to change the initial page view, and
     // inlining them would actually slow down the 99% case of "screen".
diff --git a/net/instaweb/rewriter/css_inline_filter_test.cc b/net/instaweb/rewriter/css_inline_filter_test.cc
index ea92cab..cf18524 100644
--- a/net/instaweb/rewriter/css_inline_filter_test.cc
+++ b/net/instaweb/rewriter/css_inline_filter_test.cc
@@ -156,6 +156,8 @@
     server_context()->ComputeSignature(options());
   }
 
+  bool AddHtmlTags() const override { return false; }
+
  private:
   bool filters_added_;
 };
@@ -710,6 +712,25 @@
   VerifyNoInliningForClosingStyleTag("</style abc>");
 }
 
+TEST_F(CssInlineFilterTest, DisabledForAmp) {
+  AddFilter(RewriteOptions::kInlineCss);
+  SetResponseWithDefaultHeaders("foo.css", kContentTypeCss,
+                                "/* pretend there is a @font-face here */",
+                                100);
+  TurnOnDebug();
+  ValidateExpected(
+      "no_inlining_in_amp",
+      "<html amp><link rel='stylesheet' href='foo.css'>",
+      "<html amp><link rel='stylesheet' href='foo.css'>"
+      "<!--CSS inlining not supported by PageSpeed for AMP documents-->");
+
+  // Make sure same stylesheet gets inlined elsewhere.
+  ValidateExpected(
+      "same_url_in_non_amp",
+      "<link rel='stylesheet' href='foo.css'>",
+      "<style>/* pretend there is a @font-face here */</style>");
+}
+
 }  // namespace
 
 }  // namespace net_instaweb
diff --git a/pagespeed/automatic/system_tests/inliners.sh b/pagespeed/automatic/system_tests/inliners.sh
index db55fa3..a4f5cb7 100644
--- a/pagespeed/automatic/system_tests/inliners.sh
+++ b/pagespeed/automatic/system_tests/inliners.sh
@@ -28,9 +28,8 @@
 user_agent =Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/51.0.2704.36 Safari/537.36
 EOF
 
-  fetch_until $URL 'grep -c @font-face' 7
-
-  OUT=$($WGET_DUMP $URL)
+  fetch_until -save $URL 'grep -c @font-face' 7 "" -ge
+  OUT=$(cat $FETCH_UNTIL_OUTFILE)
   check_from "$OUT" fgrep -qi "format('woff2')"
   check_not_from "$OUT" fgrep -qi "format('truetype')"
   check_not_from "$OUT" fgrep -qi "format('embedded-opentype')"
@@ -44,10 +43,10 @@
 user_agent = Mozilla/4.0 (compatible; MSIE 6.01; Windows NT 6.0)
 EOF
 
-  fetch_until $URL 'grep -c @font-face' 1
+  fetch_until -save $URL 'grep -c @font-face' 1
   # This should get an eot font. (It might also ship a woff, so we don't
   # check_not_from for that)
-  OUT=$($WGET_DUMP $URL)
+  OUT=$(cat $FETCH_UNTIL_OUTFILE)
   check_from "$OUT" fgrep -qi ".eot"
   check_not_from "$OUT" fgrep -qi ".ttf"