diff --git a/include/libtorrent/bencode.hpp b/include/libtorrent/bencode.hpp
index 7e3a7848d..a31d3629a 100644
--- a/include/libtorrent/bencode.hpp
+++ b/include/libtorrent/bencode.hpp
@@ -215,9 +215,12 @@ namespace libtorrent
 				ret += e.preformatted().size();
 				break;
 			case entry::undefined_t:
-				// trying to encode a structure with uninitialized values!
-//				TORRENT_ASSERT_VAL(false, e.type());
-				// do nothing
+
+				// empty string
+				write_char(out, '0');
+				write_char(out, ':');
+
+				ret += 2;
 				break;
 			}
 			return ret;
diff --git a/test/test_bencoding.cpp b/test/test_bencoding.cpp
index 1502437fb..25661d486 100644
--- a/test/test_bencoding.cpp
+++ b/test/test_bencoding.cpp
@@ -121,6 +121,19 @@ TORRENT_TEST(preformatted_node)
 	TEST_EQUAL(encode(e), "d4:infofoobare");
 }
 
+TORRENT_TEST(undefined_node)
+{
+	entry e(entry::undefined_t);
+	TEST_EQUAL(encode(e), "0:");
+}
+
+TORRENT_TEST(undefined_node2)
+{
+	entry e(entry::dictionary_t);
+	e["info"] = entry(entry::undefined_t);
+	TEST_EQUAL(encode(e), "d4:info0:e");
+}
+
 #ifndef TORRENT_NO_DEPRECATE
 TORRENT_TEST(lazy_entry)
 {