diff --git a/core/numeric.rbs b/core/numeric.rbs
index e8df26fe4..bc983b432 100644
--- a/core/numeric.rbs
+++ b/core/numeric.rbs
@@ -237,7 +237,7 @@ class Numeric
   #
   # No subclass in the Ruby Core or Standard Library uses this implementation.
   #
-  def <=>: (Numeric other) -> Integer
+  def <=>: (Numeric other) -> Integer?
 
   # <!--
   #   rdoc-file=numeric.c
diff --git a/test/stdlib/Numeric_test.rb b/test/stdlib/Numeric_test.rb
index cbaefa608..ad10c03c1 100644
--- a/test/stdlib/Numeric_test.rb
+++ b/test/stdlib/Numeric_test.rb
@@ -5,6 +5,12 @@ class NumericInstanceTest < Test::Unit::TestCase
 
   testing 'Numeric'
 
+  def test_op_cmp
+    numeric = Numeric.new
+    assert_send_type '(Numeric) -> 0', numeric, :<=>, numeric
+    assert_send_type '(Numeric) -> nil', numeric, :<=>, Numeric.new
+  end
+
   def test_real
     assert_send_type '() -> Integer', 1, :real
     assert_send_type '() -> Float', 1.0, :real