diff --git a/lib/itax_code/error.rb b/lib/itax_code/error.rb
index 3a7f341..2500693 100644
--- a/lib/itax_code/error.rb
+++ b/lib/itax_code/error.rb
@@ -16,5 +16,6 @@ class Parser
     InvalidControlInternalNumberError = Class.new(Error)
     InvalidTaxCodeError = Class.new(Error)
     NoTaxCodeError = Class.new(Error)
+    DateTaxCodeError = Class.new(Error)
   end
 end
diff --git a/lib/itax_code/parser.rb b/lib/itax_code/parser.rb
index dbb6796..97c1ee0 100644
--- a/lib/itax_code/parser.rb
+++ b/lib/itax_code/parser.rb
@@ -84,6 +84,8 @@ def day
 
       def birthdate
         @birthdate ||= Date.parse("#{year}-#{month}-#{day}").to_s
+      rescue ArgumentError
+        raise DateTaxCodeError
       end
 
       def birthplace(src = utils.cities, stop: false)
diff --git a/test/itax_code/parser_test.rb b/test/itax_code/parser_test.rb
index 03792a8..ba12176 100644
--- a/test/itax_code/parser_test.rb
+++ b/test/itax_code/parser_test.rb
@@ -48,6 +48,12 @@ class ParserTest < Minitest::Test
       assert_raises(klass::InvalidTaxCodeError) { klass.new(wrong_length_tax_code) }
     end
 
+    test "raises DateTaxCodeError with an invalid date, e.g. 1978-4-31" do
+      wrong_month_tax_code = "SPENTB78D71D612X"
+
+      assert_raises(klass::DateTaxCodeError) { klass.new(wrong_month_tax_code).decode }
+    end
+
     test "raises InvalidControlInternalNumberError when the cin differs from the computed one" do
       tax_code_with_wrong_cin = "CCCFBA85D03L219Z"