diff --git a/hgext/releasenotes.py b/hgext/releasenotes.py
--- a/hgext/releasenotes.py
+++ b/hgext/releasenotes.py
@@ -242,6 +242,29 @@
         read('.hgreleasenotes')
     return p['sections']
 
+def checkadmonitions(ui, repo, directives, revs):
+    """
+    Checks the commit messages for admonitions and their validity.
+
+    .. abcd::
+
+       First paragraph under this admonition
+
+    For this commit message, using `hg releasenotes -r . --check`
+    returns: Invalid admonition 'abcd' present in changeset 3ea92981e103
+
+    As admonition 'abcd' is neither present in default nor custom admonitions
+    """
+    for rev in revs:
+        ctx = repo[rev]
+        admonition = re.search(RE_DIRECTIVE, ctx.description())
+        if admonition:
+            if admonition.group(1) in directives:
+                continue
+            else:
+                ui.write(_("Invalid admonition \'%s\' present in changeset %s\
+\n") % (admonition.group(1), ctx.hex()[:12]))
+
 def parsenotesfromrevisions(repo, directives, revs):
     notes = parsedreleasenotes()
 
@@ -432,9 +455,11 @@
     return '\n'.join(lines)
 
 @command('releasenotes',
-    [('r', 'rev', '', _('revisions to process for release notes'), _('REV'))],
-    _('[-r REV] FILE'))
-def releasenotes(ui, repo, file_, rev=None):
+    [('r', 'rev', '', _('revisions to process for release notes'), _('REV')),
+    ('c', 'check', False, _('checks for validity of admonitions (if any)'),
+        _('REV'))],
+    _('hg releasenotes [-r REV] [-c] FILE'))
+def releasenotes(ui, repo, file_=None, **opts):
     """parse release notes from commit messages into an output file
 
     Given an output file and set of revisions, this command will parse commit
@@ -511,23 +536,28 @@
     release note after it has been added to the release notes file.
     """
     sections = releasenotessections(ui, repo)
+    rev = opts.get('rev')
 
     revs = scmutil.revrange(repo, [rev or 'not public()'])
-    incoming = parsenotesfromrevisions(repo, sections.names(), revs)
+    if opts.get('check'):
+        checkadmonitions(ui, repo, sections.names(), revs)
+
+    if not opts.get('check'):
+        incoming = parsenotesfromrevisions(repo, sections.names(), revs)
 
-    try:
-        with open(file_, 'rb') as fh:
-            notes = parsereleasenotesfile(sections, fh.read())
-    except IOError as e:
-        if e.errno != errno.ENOENT:
-            raise
+        try:
+            with open(file_, 'rb') as fh:
+                notes = parsereleasenotesfile(sections, fh.read())
+        except IOError as e:
+            if e.errno != errno.ENOENT:
+                raise
 
-        notes = parsedreleasenotes()
+            notes = parsedreleasenotes()
 
-    notes.merge(ui, incoming)
+        notes.merge(ui, incoming)
 
-    with open(file_, 'wb') as fh:
-        fh.write(serializenotes(sections, notes))
+        with open(file_, 'wb') as fh:
+            fh.write(serializenotes(sections, notes))
 
 @command('debugparsereleasenotes', norepo=True)
 def debugparsereleasenotes(ui, path, repo=None):