diff --git a/ChangeLog b/ChangeLog
index 048199595f..9a639f3153 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Wed Apr  3 16:34:24 2013  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* bignum.c (rb_big_eq): test as Fixnum if possible and get rid of zero
+	  length Bignum.  [ruby-core:53893] [Bug #8204]
+
 Tue Apr  2 23:56:03 2013  Tanaka Akira  <akr@fsij.org>
 
 	* lib/securerandom.rb (SecureRandom.random_bytes): Use
diff --git a/bignum.c b/bignum.c
index 54dd75cf89..6d2b25f997 100644
--- a/bignum.c
+++ b/bignum.c
@@ -1686,6 +1686,7 @@ rb_big_eq(VALUE x, VALUE y)
 {
     switch (TYPE(y)) {
       case T_FIXNUM:
+	if (bignorm(x) == y) return Qtrue;
 	y = rb_int2big(FIX2LONG(y));
 	break;
       case T_BIGNUM:
diff --git a/ext/-test-/bignum/bigzero.c b/ext/-test-/bignum/bigzero.c
new file mode 100644
index 0000000000..5181d71aab
--- /dev/null
+++ b/ext/-test-/bignum/bigzero.c
@@ -0,0 +1,16 @@
+#include "ruby.h"
+
+static VALUE
+bug_big_zero(VALUE self, VALUE length)
+{
+    long len = NUM2ULONG(length);
+    VALUE z = rb_big_new(len, 1);
+    MEMZERO(RBIGNUM_DIGITS(z), BDIGIT, len);
+    return z;
+}
+
+void
+Init_bigzero(VALUE klass)
+{
+    rb_define_singleton_method(klass, "zero", bug_big_zero, 1);
+}
diff --git a/ext/-test-/bignum/extconf.rb b/ext/-test-/bignum/extconf.rb
new file mode 100644
index 0000000000..4ced662180
--- /dev/null
+++ b/ext/-test-/bignum/extconf.rb
@@ -0,0 +1,6 @@
+$srcs = Dir[File.join($srcdir, "*.{#{SRC_EXT.join(%q{,})}}")]
+inits = $srcs.map {|s| File.basename(s, ".*")}
+inits.delete("init")
+inits.map! {|s|"X(#{s})"}
+$defs << "-DTEST_INIT_FUNCS(X)=\"#{inits.join(' ')}\""
+create_makefile("-test-/bignum")
diff --git a/ext/-test-/bignum/init.c b/ext/-test-/bignum/init.c
new file mode 100644
index 0000000000..82a159bf1d
--- /dev/null
+++ b/ext/-test-/bignum/init.c
@@ -0,0 +1,11 @@
+#include "ruby.h"
+
+#define init(n) {void Init_##n(VALUE klass); Init_##n(klass);}
+
+void
+Init_bignum(void)
+{
+    VALUE mBug = rb_define_module("Bug");
+    VALUE klass = rb_define_class_under(mBug, "Bignum", rb_cString);
+    TEST_INIT_FUNCS(init);
+}
diff --git a/test/-ext-/bignum/test_bigzero.rb b/test/-ext-/bignum/test_bigzero.rb
new file mode 100644
index 0000000000..f75c4590b8
--- /dev/null
+++ b/test/-ext-/bignum/test_bigzero.rb
@@ -0,0 +1,13 @@
+require 'test/unit'
+require "-test-/bignum"
+
+class TestBignum < Test::Unit::TestCase
+  class TestBigZero < Test::Unit::TestCase
+    def test_equal_0
+      bug8204 = '[ruby-core:53893] [Bug #8204]'
+      (0..10).each do |i|
+        assert_equal(0, Bug::Bignum.zero(i), "#{bug8204} Bignum.zero(#{i})")
+      end
+    end
+  end
+end