diff --git a/README.md b/README.md
index 98150c9..63c06c5 100644
--- a/README.md
+++ b/README.md
@@ -16,7 +16,8 @@ Executing `./check_http_json.py -h` will yield the following details:
 
 ```
 usage: check_http_json.py [-h] [-d] [-s] -H HOST [-P PORT] [-p PATH]
-                          [-t TIMEOUT] [-B AUTH] [-D DATA] [-f SEPARATOR]
+                          [-t TIMEOUT] [-B AUTH] [-D DATA] [-A HEADERS]
+                          [-f SEPARATOR]
                           [-w [KEY_THRESHOLD_WARNING [KEY_THRESHOLD_WARNING ...]]]
                           [-c [KEY_THRESHOLD_CRITICAL [KEY_THRESHOLD_CRITICAL ...]]]
                           [-e [KEY_LIST [KEY_LIST ...]]]
@@ -41,6 +42,8 @@ optional arguments:
   -B AUTH, --basic-auth AUTH
                         Basic auth string "username:password"
   -D DATA, --data DATA  The http payload to send as a POST
+  -A HEADERS, --headers HEADERS
+                        The http headers in JSON format.
   -f SEPARATOR, --field_separator SEPARATOR
                         Json Field separator, defaults to "." ; Select element
                         in an array with "(" ")"
@@ -156,6 +159,10 @@ optional arguments:
 
 More info about Nagios Range format and Units of Measure can be found at [https://nagios-plugins.org/doc/guidelines.html](https://nagios-plugins.org/doc/guidelines.html).
 
+#### Using Headers 
+
+* `./check_http_json.py -H <host>:<port> -p <path> -A '{"content-type": "application/json"}' -w "metric,RANGE"`
+
 ## Nagios Installation
 
 ### Requirements
diff --git a/check_http_json.py b/check_http_json.py
index 05a65df..8dd1327 100755
--- a/check_http_json.py
+++ b/check_http_json.py
@@ -56,7 +56,7 @@ class NagiosHelper:
 	def append_critical(self, critical_message):
 		self.critical_message += critical_message
 	def append_unknown(self, unknown_message):
-		self.critical_message += critical_message
+		self.critical_message += unknown_message
 	def append_metrics(self, (performance_data, warning_message, critical_message)):
 		self.performance_data += performance_data
 		self.append_warning(warning_message)
@@ -275,6 +275,7 @@ def parseArgs():
 	parser.add_argument('-t', '--timeout', type=int, help='Connection timeout (seconds)')
 	parser.add_argument('-B', '--basic-auth', dest='auth', help='Basic auth string "username:password"')
 	parser.add_argument('-D', '--data', dest='data', help='The http payload to send as a POST')
+	parser.add_argument('-A', '--headers', dest='headers', help='The http headers in JSON format.')
 	parser.add_argument('-f', '--field_separator', dest='separator',
 		help='Json Field separator, defaults to "." ; Select element in an array with "(" ")"')
 	parser.add_argument('-w', '--warning', dest='key_threshold_warning', nargs='*',
@@ -409,6 +410,11 @@ if __name__ == "__main__":
 		if args.auth:
 			base64str = base64.encodestring(args.auth).replace('\n', '')
 			req.add_header('Authorization', 'Basic %s' % base64str)
+		if args.headers:
+			headers=json.loads(args.headers)
+			debugPrint(args.debug, "Headers:\n %s" % headers)
+			for header in headers:
+				req.add_header(header, headers[header])
 		if args.timeout and args.data:
 			response = urllib2.urlopen(req, timeout=args.timeout, data=args.data)
 		elif args.timeout: