diff --git a/lib/csv.rb b/lib/csv.rb
index 31e46d91..17b9836d 100644
--- a/lib/csv.rb
+++ b/lib/csv.rb
@@ -875,10 +875,9 @@ def initialize(message, line_number)
   # A Regexp used to find and convert some common DateTime formats.
   DateTimeMatcher =
     / \A(?: (\w+,?\s+)?\w+\s+\d{1,2}\s+\d{1,2}:\d{1,2}:\d{1,2},?\s+\d{2,4} |
-            \d{4}-\d{2}-\d{2}\s\d{2}:\d{2}:\d{2} |
-            # ISO-8601
+            # ISO-8601 and RFC-3339 (space instead of T) recognized by DateTime.parse
             \d{4}-\d{2}-\d{2}
-              (?:T\d{2}:\d{2}(?::\d{2}(?:\.\d+)?(?:[+-]\d{2}(?::\d{2})|Z)?)?)?
+              (?:[T\s]\d{2}:\d{2}(?::\d{2}(?:\.\d+)?(?:[+-]\d{2}(?::\d{2})|Z)?)?)?
         )\z /x
 
   # The encoding used by all converters.
diff --git a/test/csv/test_data_converters.rb b/test/csv/test_data_converters.rb
index 1620e077..c20a5d1f 100644
--- a/test/csv/test_data_converters.rb
+++ b/test/csv/test_data_converters.rb
@@ -103,4 +103,88 @@ def test_builtin_date_time_converter_iso8601_utc
     assert_equal(datetime,
                  CSV::Converters[:date_time][iso8601_string])
   end
+
+  def test_builtin_date_time_converter_rfc3339_minute
+    rfc3339_string = "2018-01-14 22:25"
+    datetime = DateTime.new(2018, 1, 14, 22, 25)
+    assert_equal(datetime,
+                 CSV::Converters[:date_time][rfc3339_string])
+  end
+
+  def test_builtin_date_time_converter_rfc3339_second
+    rfc3339_string = "2018-01-14 22:25:19"
+    datetime = DateTime.new(2018, 1, 14, 22, 25, 19)
+    assert_equal(datetime,
+                 CSV::Converters[:date_time][rfc3339_string])
+  end
+
+  def test_builtin_date_time_converter_rfc3339_under_second
+    rfc3339_string = "2018-01-14 22:25:19.1"
+    datetime = DateTime.new(2018, 1, 14, 22, 25, 19.1)
+    assert_equal(datetime,
+                 CSV::Converters[:date_time][rfc3339_string])
+  end
+
+  def test_builtin_date_time_converter_rfc3339_under_second_offset
+    rfc3339_string = "2018-01-14 22:25:19.1+09:00"
+    datetime = DateTime.new(2018, 1, 14, 22, 25, 19.1, "+9")
+    assert_equal(datetime,
+                 CSV::Converters[:date_time][rfc3339_string])
+  end
+
+  def test_builtin_date_time_converter_rfc3339_offset
+    rfc3339_string = "2018-01-14 22:25:19+09:00"
+    datetime = DateTime.new(2018, 1, 14, 22, 25, 19, "+9")
+    assert_equal(datetime,
+                 CSV::Converters[:date_time][rfc3339_string])
+  end
+
+  def test_builtin_date_time_converter_rfc3339_utc
+    rfc3339_string = "2018-01-14 22:25:19Z"
+    datetime = DateTime.new(2018, 1, 14, 22, 25, 19)
+    assert_equal(datetime,
+                 CSV::Converters[:date_time][rfc3339_string])
+  end
+
+  def test_builtin_date_time_converter_rfc3339_tab_minute
+    rfc3339_string = "2018-01-14\t22:25"
+    datetime = DateTime.new(2018, 1, 14, 22, 25)
+    assert_equal(datetime,
+                 CSV::Converters[:date_time][rfc3339_string])
+  end
+
+  def test_builtin_date_time_converter_rfc3339_tab_second
+    rfc3339_string = "2018-01-14\t22:25:19"
+    datetime = DateTime.new(2018, 1, 14, 22, 25, 19)
+    assert_equal(datetime,
+                 CSV::Converters[:date_time][rfc3339_string])
+  end
+
+  def test_builtin_date_time_converter_rfc3339_tab_under_second
+    rfc3339_string = "2018-01-14\t22:25:19.1"
+    datetime = DateTime.new(2018, 1, 14, 22, 25, 19.1)
+    assert_equal(datetime,
+                 CSV::Converters[:date_time][rfc3339_string])
+  end
+
+  def test_builtin_date_time_converter_rfc3339_tab_under_second_offset
+    rfc3339_string = "2018-01-14\t22:25:19.1+09:00"
+    datetime = DateTime.new(2018, 1, 14, 22, 25, 19.1, "+9")
+    assert_equal(datetime,
+                 CSV::Converters[:date_time][rfc3339_string])
+  end
+
+  def test_builtin_date_time_converter_rfc3339_tab_offset
+    rfc3339_string = "2018-01-14\t22:25:19+09:00"
+    datetime = DateTime.new(2018, 1, 14, 22, 25, 19, "+9")
+    assert_equal(datetime,
+                 CSV::Converters[:date_time][rfc3339_string])
+  end
+
+  def test_builtin_date_time_converter_rfc3339_tab_utc
+    rfc3339_string = "2018-01-14\t22:25:19Z"
+    datetime = DateTime.new(2018, 1, 14, 22, 25, 19)
+    assert_equal(datetime,
+                 CSV::Converters[:date_time][rfc3339_string])
+  end
 end