diff --git a/n2cw/aws.py b/n2cw/aws.py
index 7c83200..10a9c00 100644
--- a/n2cw/aws.py
+++ b/n2cw/aws.py
@@ -1,8 +1,8 @@
 import botocore.session
 import urllib2
 
-
 AWS_MD_AZ_URL = 'http://169.254.169.254/latest/meta-data/placement/availability-zone'
+AWS_INSTANZE_ID_URL = 'http://169.254.169.254/latest/meta-data/instance-id'
 
 
 def detect_region():
@@ -11,6 +11,12 @@ def detect_region():
     except urllib2.URLError:
         return None
 
+def detect_instance_id():
+    try:
+        return urllib2.urlopen(AWS_INSTANZE_ID_URL, timeout=1).read()[:-1]
+    except urllib2.URLError:
+        return None
+
 
 def cloudwatch_client(profile=None, region=None):
     if region is None:
@@ -21,7 +27,6 @@ def cloudwatch_client(profile=None, region=None):
         session.set_config_variable('profile', profile)
     return session.create_client('cloudwatch')
 
-
 class TestClient(object):
     def __init__(self):
         import logging
@@ -33,13 +38,17 @@ def put_metric_data(self, **kwargs):
 
 
 class CW(object):
-    def __init__(self, namespace, base_name, dimensions=None, test=False):
+    def __init__(self, namespace, base_name, instance_id = False, dimensions=None, test=False):
         self.namespace = namespace
         self.base_name = base_name
         self.dimensions = []
+        self.data = []
+
         for k, v in dimensions.iteritems():
             self.dimensions.append({'Name': k, 'Value': v})
-        self.data = []
+
+        if instance_id:
+            self.dimensions.append({'Name': 'instance-id', 'Value': detect_instance_id()})
 
         if test:
             self.client = TestClient()
diff --git a/n2cw/cli.py b/n2cw/cli.py
index bcaf083..328b1e3 100644
--- a/n2cw/cli.py
+++ b/n2cw/cli.py
@@ -31,6 +31,8 @@ def cli(args=sys.argv[:]):
     ap = ArgumentParser(usage=usage, description=__doc__)
     ap.add_argument('--dimensions', metavar='key=value,key=value', default={},
                     action=ParseKv, help='CloudWatch metric dimensions')
+    ap.add_argument('--instance_id', action='store_true', 
+                    help='Add instance-id as a dimension\nWARNING: Will overwrite instance-id given via --dimensions option')
     ap.add_argument('--noop', action='store_true',
                     help='Don\'t push metrics, just log')
     ap.add_argument('namespace', help='CloudWatch namespace')
@@ -54,7 +56,7 @@ def cli(args=sys.argv[:]):
         result = e.returncode
         output = e.output
 
-    cw = aws.CW(args.namespace, args.base_name, args.dimensions, args.noop)
+    cw = aws.CW(args.namespace, args.base_name, args.instance_id, args.dimensions, args.noop)
     if args.send_status:
         cw.add('Status', result)
     if args.send_perfdata: