diff --git a/rational.c b/rational.c
index 4bdc695dc1..742f594f65 100644
--- a/rational.c
+++ b/rational.c
@@ -2396,6 +2396,7 @@ read_rat_nos(const char **s, int sign, int strict, VALUE *num)
     if (**s == '/') {
 	(*s)++;
 	if (!read_digits(s, strict, &den, NULL)) goto failed;
+	if (den == ZERO) rb_num_zerodiv();
 	nurat_reduce(num, &den);
 	if (div != ONE && den != ONE)
 	    den = rb_int_mul(den, div);
diff --git a/test/ruby/test_rational.rb b/test/ruby/test_rational.rb
index 6185611a5c..ed4c5b1006 100644
--- a/test/ruby/test_rational.rb
+++ b/test/ruby/test_rational.rb
@@ -776,6 +776,11 @@ class Rational_Test < Test::Unit::TestCase
     ng[5, 3, '5/3x']
   end
 
+  def test_parse_zero_denominator
+    assert_raise(ZeroDivisionError) {"1/0".to_r}
+    assert_raise(ZeroDivisionError) {Rational("1/0")}
+  end
+
   def test_to_i
     assert_equal(1, Rational(3,2).to_i)
     assert_equal(1, Integer(Rational(3,2)))