diff --git a/lib/cmdlib.py b/lib/cmdlib.py
index f929cd32490d7e44312883eaff5c5cfcd433d962..481b1255a11161055485ed7118b5b65a3069d4df 100644
--- a/lib/cmdlib.py
+++ b/lib/cmdlib.py
@@ -3072,9 +3072,11 @@ class LUDiagnoseOS(NoHooksLU):
     ("names", _EmptyList, _TListOf(_TNonEmptyString)),
     ]
   REQ_BGL = False
+  _HID = "hidden"
+  _BLK = "blacklisted"
   _FIELDS_STATIC = utils.FieldSet()
   _FIELDS_DYNAMIC = utils.FieldSet("name", "valid", "node_status", "variants",
-                                   "parameters", "api_versions")
+                                   "parameters", "api_versions", _HID, _BLK)
 
   def CheckArguments(self):
     if self.op.names:
@@ -3141,6 +3143,7 @@ class LUDiagnoseOS(NoHooksLU):
     node_data = self.rpc.call_os_diagnose(valid_nodes)
     pol = self._DiagnoseByOS(node_data)
     output = []
+    cluster = self.cfg.GetClusterInfo()
 
     for os_name, os_data in pol.items():
       row = []
@@ -3161,6 +3164,12 @@ class LUDiagnoseOS(NoHooksLU):
           params.intersection_update(node_params)
           api_versions.intersection_update(node_api)
 
+      is_hid = os_name in cluster.hidden_oss
+      is_blk = os_name in cluster.blacklisted_oss
+      if ((self._HID not in self.op.output_fields and is_hid) or
+          (self._BLK not in self.op.output_fields and is_blk)):
+        continue
+
       for field in self.op.output_fields:
         if field == "name":
           val = os_name
@@ -3177,6 +3186,10 @@ class LUDiagnoseOS(NoHooksLU):
           val = list(params)
         elif field == "api_versions":
           val = list(api_versions)
+        elif field == self._HID:
+          val = is_hid
+        elif field == self._BLK:
+          val = is_blk
         else:
           raise errors.ParameterError(field)
         row.append(val)
diff --git a/man/gnt-os.sgml b/man/gnt-os.sgml
index 7cf9d4d84d7dd8daa2b8b07cbeb2b2f366f7abd6..d4b698b7432c546d36f566456a32f9369bdc7fc1 100644
--- a/man/gnt-os.sgml
+++ b/man/gnt-os.sgml
@@ -2,7 +2,7 @@
 
   <!-- Fill in your name for FIRSTNAME and SURNAME. -->
   <!-- Please adjust the date whenever revising the manpage. -->
-  <!ENTITY dhdate      "<date>June 08, 2010</date>">
+  <!ENTITY dhdate      "<date>September 20, 2010</date>">
   <!-- SECTION should be 1-8, maybe w/ subsection other parameters are
        allowed: see man(7), man(1). -->
   <!ENTITY dhsection   "<manvolnum>8</manvolnum>">
@@ -69,6 +69,11 @@
       as an option.
     </para>
 
+    <para>
+      Note that hidden or blacklisted OSes are not displayed by this
+      command, use <command>diagnose</command> for showing those.
+    </para>
+
     <cmdsynopsis>
       <command>diagnose</command>
     </cmdsynopsis>
diff --git a/scripts/gnt-os b/scripts/gnt-os
index 4fac7375a3a342ee9a09763507d6f0f1284af143..6c419bd6cb6ae8283b0b3bac323d3b56c1c6b059 100755
--- a/scripts/gnt-os
+++ b/scripts/gnt-os
@@ -82,7 +82,8 @@ def ShowOSInfo(opts, args):
 
   """
   op = opcodes.OpDiagnoseOS(output_fields=["name", "valid", "variants",
-                                           "parameters", "api_versions"],
+                                           "parameters", "api_versions",
+                                           "blacklisted", "hidden"],
                             names=[])
   result = SubmitOpCode(op, opts=opts)
 
@@ -92,7 +93,7 @@ def ShowOSInfo(opts, args):
 
   do_filter = bool(args)
 
-  for (name, valid, variants, parameters, api_versions) in result:
+  for (name, valid, variants, parameters, api_versions, blk, hid) in result:
     if do_filter:
       if name not in args:
         continue
@@ -100,6 +101,8 @@ def ShowOSInfo(opts, args):
         args.remove(name)
     ToStdout("%s:", name)
     ToStdout("  - valid: %s", valid)
+    ToStdout("  - hidden: %s", hid)
+    ToStdout("  - blacklisted: %s", blk)
     if valid:
       ToStdout("  - API versions:")
       for version in sorted(api_versions):
@@ -148,7 +151,8 @@ def DiagnoseOS(opts, args):
 
   """
   op = opcodes.OpDiagnoseOS(output_fields=["name", "valid", "variants",
-                                           "node_status"], names=[])
+                                           "node_status", "hidden",
+                                           "blacklisted"], names=[])
   result = SubmitOpCode(op, opts=opts)
 
   if not result:
@@ -157,7 +161,7 @@ def DiagnoseOS(opts, args):
 
   has_bad = False
 
-  for os_name, _, os_variants, node_data in result:
+  for os_name, _, os_variants, node_data, hid, blk in result:
     nodes_valid = {}
     nodes_bad = {}
     nodes_hidden = {}
@@ -173,6 +177,7 @@ def DiagnoseOS(opts, args):
         else:
           max_os_api = 0
           fo_msg += " [no API versions declared]"
+
         if max_os_api >= constants.OS_API_V15:
           if fo_variants:
             fo_msg += " [variants: %s]" % utils.CommaJoin(fo_variants)
@@ -210,7 +215,12 @@ def DiagnoseOS(opts, args):
         for msg in nodes_hidden[node_name]:
           ToStdout(msg)
 
-    ToStdout("OS: %s [global status: %s]", os_name, status)
+    st_msg = "OS: %s [global status: %s]" % (os_name, status)
+    if hid:
+      st_msg += " [hidden]"
+    if blk:
+      st_msg += " [blacklisted]"
+    ToStdout(st_msg)
     if os_variants:
       ToStdout("  Variants: [%s]" % utils.CommaJoin(os_variants))
     _OutputPerNodeOSStatus(nodes_valid)