diff --git a/swift/common/utils.py b/swift/common/utils.py
index 787c3c2363..c78572f402 100644
--- a/swift/common/utils.py
+++ b/swift/common/utils.py
@@ -939,11 +939,16 @@ class Timestamp(object):
         :param delta: deca-microsecond difference from the base timestamp
                       param, an int
         """
+        if isinstance(timestamp, bytes):
+            timestamp = timestamp.decode('ascii')
         if isinstance(timestamp, six.string_types):
-            parts = timestamp.split('_', 1)
-            self.timestamp = float(parts.pop(0))
-            if parts:
-                self.offset = int(parts[0], 16)
+            base, base_offset = timestamp.partition('_')[::2]
+            self.timestamp = float(base)
+            if '_' in base_offset:
+                raise ValueError('invalid literal for int() with base 16: '
+                                 '%r' % base_offset)
+            if base_offset:
+                self.offset = int(base_offset, 16)
             else:
                 self.offset = 0
         else:
diff --git a/test/unit/common/test_utils.py b/test/unit/common/test_utils.py
index af0bf9e967..c90a03a5f6 100644
--- a/test/unit/common/test_utils.py
+++ b/test/unit/common/test_utils.py
@@ -183,6 +183,7 @@ class TestTimestamp(unittest.TestCase):
 
     def test_invalid_input(self):
         self.assertRaises(ValueError, utils.Timestamp, time.time(), offset=-1)
+        self.assertRaises(ValueError, utils.Timestamp, '123.456_78_90')
 
     def test_invalid_string_conversion(self):
         t = utils.Timestamp.now()
@@ -390,6 +391,8 @@ class TestTimestamp(unittest.TestCase):
         expected = '1402436408.91203_00000000000000f0'
         test_values = (
             '1402436408.91203_000000f0',
+            u'1402436408.91203_000000f0',
+            b'1402436408.91203_000000f0',
             '1402436408.912030000_0000000000f0',
             '1402436408.912029_000000f0',
             '1402436408.91202999999_0000000000f0',