diff --git a/.isort.cfg b/.isort.cfg
index e141924..e8d95f8 100644
--- a/.isort.cfg
+++ b/.isort.cfg
@@ -1,7 +1,7 @@
 [settings]
 check=1
 diff=1
-known_third_party=dateutil,pytest,pytz,six,requests,taxii2_client
+known_third_party=dateutil,pytest,pytz,six,requests,taxii2client
 known_first_party=stix2
 not_skip=__init__.py
 force_sort_within_sections=1
diff --git a/README.rst b/README.rst
index b2a8c9c..03c7cc3 100644
--- a/README.rst
+++ b/README.rst
@@ -39,8 +39,8 @@ constructor:
     from stix2 import Indicator
 
     indicator = Indicator(name="File hash for malware variant",
-                          labels=['malicious-activity'],
-                          pattern='file:hashes.md5 = "d41d8cd98f00b204e9800998ecf8427e"')
+                          labels=["malicious-activity"],
+                          pattern="[file:hashes.md5 = 'd41d8cd98f00b204e9800998ecf8427e']")
 
 Certain required attributes of all objects will be set automatically if
 not provided as keyword arguments:
diff --git a/setup.py b/setup.py
index c10da46..2b8d544 100644
--- a/setup.py
+++ b/setup.py
@@ -52,6 +52,8 @@ setup(
         'pytz',
         'requests',
         'simplejson',
-        'six'
+        'six',
+        'stix2-patterns',
+        'taxii2-client',
     ],
 )
diff --git a/stix2/properties.py b/stix2/properties.py
index f63ec8b..a04294e 100644
--- a/stix2/properties.py
+++ b/stix2/properties.py
@@ -7,6 +7,8 @@ import uuid
 
 from six import string_types, text_type
 
+from stix2patterns.validator import run_validator
+
 from .base import _STIXBase
 from .exceptions import DictionaryKeyError
 from .utils import get_dict, parse_into_datetime
@@ -370,3 +372,17 @@ class EnumProperty(StringProperty):
         if value not in self.allowed:
             raise ValueError("value '%s' is not valid for this enumeration." % value)
         return self.string_type(value)
+
+
+class PatternProperty(StringProperty):
+
+    def __init__(self, **kwargs):
+        super(PatternProperty, self).__init__(**kwargs)
+
+    def clean(self, value):
+        str_value = super(PatternProperty, self).clean(value)
+        errors = run_validator(str_value)
+        if errors:
+            raise ValueError(str(errors[0]))
+
+        return self.string_type(value)
diff --git a/stix2/sdo.py b/stix2/sdo.py
index b2b0e7e..7eebf56 100644
--- a/stix2/sdo.py
+++ b/stix2/sdo.py
@@ -11,8 +11,8 @@ from .base import _STIXBase
 from .common import ExternalReference, GranularMarking, KillChainPhase
 from .observables import ObservableProperty
 from .properties import (BooleanProperty, IDProperty, IntegerProperty,
-                         ListProperty, ReferenceProperty, StringProperty,
-                         TimestampProperty, TypeProperty)
+                         ListProperty, PatternProperty, ReferenceProperty,
+                         StringProperty, TimestampProperty, TypeProperty)
 from .utils import NOW
 
 
@@ -117,7 +117,7 @@ class Indicator(_STIXBase):
         ('labels', ListProperty(StringProperty, required=True)),
         ('name', StringProperty()),
         ('description', StringProperty()),
-        ('pattern', StringProperty(required=True)),
+        ('pattern', PatternProperty(required=True)),
         ('valid_from', TimestampProperty(default=lambda: NOW)),
         ('valid_until', TimestampProperty()),
         ('kill_chain_phases', ListProperty(KillChainPhase)),
diff --git a/stix2/test/test_data_sources.py b/stix2/test/test_data_sources.py
index bbb7f31..0095802 100644
--- a/stix2/test/test_data_sources.py
+++ b/stix2/test/test_data_sources.py
@@ -1,5 +1,5 @@
 import pytest
-from taxii2_client import Collection
+from taxii2client import Collection
 
 from stix2.sources import DataSource, Filter, taxii
 
diff --git a/stix2/test/test_indicator.py b/stix2/test/test_indicator.py
index 5a7ae5a..1f8e3bd 100644
--- a/stix2/test/test_indicator.py
+++ b/stix2/test/test_indicator.py
@@ -174,3 +174,23 @@ def test_parse_indicator(data):
     assert idctr.valid_from == dt.datetime(1970, 1, 1, 0, 0, 1, tzinfo=pytz.utc)
     assert idctr.labels[0] == "malicious-activity"
     assert idctr.pattern == "[file:hashes.MD5 = 'd41d8cd98f00b204e9800998ecf8427e']"
+
+
+def test_invalid_indicator_pattern():
+    with pytest.raises(stix2.exceptions.InvalidValueError) as excinfo:
+        stix2.Indicator(
+            labels=['malicious-activity'],
+            pattern="file:hashes.MD5 = 'd41d8cd98f00b204e9800998ecf8427e'",
+        )
+    assert excinfo.value.cls == stix2.Indicator
+    assert excinfo.value.prop_name == 'pattern'
+    assert 'input is missing square brackets' in excinfo.value.reason
+
+    with pytest.raises(stix2.exceptions.InvalidValueError) as excinfo:
+        stix2.Indicator(
+            labels=['malicious-activity'],
+            pattern='[file:hashes.MD5 = "d41d8cd98f00b204e9800998ecf8427e"]',
+        )
+    assert excinfo.value.cls == stix2.Indicator
+    assert excinfo.value.prop_name == 'pattern'
+    assert 'mismatched input' in excinfo.value.reason