diff --git a/toscaparser/nodetemplate.py b/toscaparser/nodetemplate.py
index 5b456b1..f93c560 100644
--- a/toscaparser/nodetemplate.py
+++ b/toscaparser/nodetemplate.py
@@ -54,7 +54,7 @@ class NodeTemplate(EntityTemplate):
     def relationships(self):
         if not self._relationships:
             requires = self.requirements
-            if requires:
+            if requires and isinstance(requires, list):
                 for r in requires:
                     for r1, value in r.items():
                         explicit = self._get_explicit_relationship(r, value)
@@ -206,13 +206,15 @@ class NodeTemplate(EntityTemplate):
                     TypeMismatchError(
                         what='"requirements" of template "%s"' % self.name,
                         type='list'))
-            for req in requires:
-                for r1, value in req.items():
-                    if isinstance(value, dict):
-                        self._validate_requirements_keys(value)
-                        self._validate_requirements_properties(value)
-                        allowed_reqs.append(r1)
-                self._common_validate_field(req, allowed_reqs, 'requirements')
+            else:
+                for req in requires:
+                    for r1, value in req.items():
+                        if isinstance(value, dict):
+                            self._validate_requirements_keys(value)
+                            self._validate_requirements_properties(value)
+                            allowed_reqs.append(r1)
+                    self._common_validate_field(req, allowed_reqs,
+                                                'requirements')
 
     def _validate_requirements_properties(self, requirements):
         # TODO(anyone): Only occurrences property of the requirements is
diff --git a/toscaparser/tests/test_toscatplvalidation.py b/toscaparser/tests/test_toscatplvalidation.py
index 7af4f17..ecc5765 100644
--- a/toscaparser/tests/test_toscatplvalidation.py
+++ b/toscaparser/tests/test_toscatplvalidation.py
@@ -1707,3 +1707,54 @@ heat-translator/master/translator/tests/data/custom_types/wordpress.yaml
             toscaparser.utils.yamlparser.simple_parse(
                 tpl_snippet_qualified_name))
         TopologyTemplate(tpl, None)
+
+    def test_requirements_as_list(self):
+        """Node template with requirements provided with or without list
+
+        Node template requirements are required to be provided as list.
+        """
+
+        expectedmessage = _('"requirements" of template "my_webserver"'
+                            ' must be of type "list".')
+
+        # requirements provided as dictionary
+        tpl_snippet1 = '''
+        node_templates:
+          my_webserver:
+            type: tosca.nodes.WebServer
+            requirements:
+              host: server
+          server:
+            type: tosca.nodes.Compute
+        '''
+        err1 = self.assertRaises(
+            exception.TypeMismatchError,
+            lambda: self._single_node_template_content_test(tpl_snippet1))
+        self.assertEqual(expectedmessage, err1.__str__())
+
+        # requirements provided as string
+        tpl_snippet2 = '''
+        node_templates:
+          my_webserver:
+            type: tosca.nodes.WebServer
+            requirements: server
+          server:
+            type: tosca.nodes.Compute
+        '''
+        err2 = self.assertRaises(
+            exception.TypeMismatchError,
+            lambda: self._single_node_template_content_test(tpl_snippet2))
+        self.assertEqual(expectedmessage, err2.__str__())
+
+        # requirements provided as list
+        tpl_snippet3 = '''
+        node_templates:
+          my_webserver:
+            type: tosca.nodes.WebServer
+            requirements:
+              - host: server
+          server:
+            type: tosca.nodes.Compute
+        '''
+        self.assertIsNone(
+            self._single_node_template_content_test(tpl_snippet3))
diff --git a/toscaparser/topology_template.py b/toscaparser/topology_template.py
index 463e083..763eeb9 100644
--- a/toscaparser/topology_template.py
+++ b/toscaparser/topology_template.py
@@ -259,7 +259,8 @@ class TopologyTemplate(object):
                                 self,
                                 node_template,
                                 value)
-                if node_template.requirements:
+                if node_template.requirements and \
+                   isinstance(node_template.requirements, list):
                     for req in node_template.requirements:
                         rel = req
                         for req_name, req_item in req.items():