diff --git a/lccs/cli.py b/lccs/cli.py
index 9276a8a..be30c2a 100644
--- a/lccs/cli.py
+++ b/lccs/cli.py
@@ -177,7 +177,7 @@ def mappings(config: Config, system_name_source, system_name_target, verbose):
 @click.option('--system_name_source', type=click.STRING, required=True, help='The classification system source.')
 @click.option('--system_name_target', type=click.STRING, required=True, default=None,
               help='The classification system target.')
-@click.option('--mappings_path', type=click.Path(exists=True), required=True,  help='File path with the mapping')
+@click.option('--mappings_path', type=click.Path(exists=True), required=True,  help='Json file with the mapping')
 @click.option('-v', '--verbose', is_flag=True, default=False)
 @pass_config
 def add_mapping(config: Config, system_name_source, system_name_target, mappings_path, verbose):
@@ -187,8 +187,8 @@ def add_mapping(config: Config, system_name_source, system_name_target, mappings
         click.secho('\tAdding new mapping ... ', bold=False, fg='black')
 
     config.service.add_mapping(system_name_source=system_name_source,
-                                        system_name_target=system_name_target,
-                                        mappings=mappings_path)
+                               system_name_target=system_name_target,
+                               mappings=mappings_path)
 
     click.secho(f'Added Mapping between {system_name_source} and '
                 f'{system_name_target}', bold=True, fg='green')
@@ -243,3 +243,22 @@ def add_classification_system(config: Config, name, authority_name, description,
 
     if verbose:
         click.secho('\tFinished!', bold=False, fg='black')
+
+
+@cli.command()
+@click.option('--system_name', type=click.STRING, required=True, help='The classification system.')
+@click.option('--classes_path', type=click.Path(exists=True), required=True,  help='Json file with classes')
+@click.option('-v', '--verbose', is_flag=True, default=False)
+@pass_config
+def add_classes(config: Config, system_name, classes_path, verbose):
+    """Add a mapping between classification systems."""
+    if verbose:
+        click.secho(f'Server: {config.url}', bold=True, fg='black')
+        click.secho('\tAdding new mapping ... ', bold=False, fg='black')
+
+    config.service.add_classes(system_name=system_name, classes=classes_path)
+
+    click.secho(f'Added classes for {system_name}', bold=True, fg='green')
+
+    if verbose:
+        click.secho('\tFinished!', bold=False, fg='black')
diff --git a/lccs/lccs.py b/lccs/lccs.py
index ea00db9..34ea9bf 100644
--- a/lccs/lccs.py
+++ b/lccs/lccs.py
@@ -214,6 +214,30 @@ def add_classification_system(self, name: str, authority_name: str, description:
             raise ValueError(f'Could not insert classification system {name}!')
         
         return retval
+
+    def add_classes(self, system_name, classes: str):
+        """Add new classes to an classification system."""
+        _system_id = self._id(system_name)
+
+        url = f'{self._url}/classification_systems/{_system_id.id}/classes{self._access_token}'
+
+        if type(classes) == str:
+            with open(classes) as file:
+                classes = json.load(file)
+
+        for i in classes:
+            if 'class_parent_id' not in i:
+                break
+            if type(i['class_parent_id']) != str:
+                break
+            i['class_parent_id'] = Utils.get_id_by_name(name=i['class_parent_id'], classes=_system_id.classes)
+
+        try:
+            retval = Utils._post(url, json=classes)
+        except RuntimeError:
+            raise ValueError('Could not insert classes!')
+
+        return retval
     
     def add_style(self, system_name: str, format_name: str, style_path: str):
         """Add a new style format system."""
@@ -240,10 +264,6 @@ def add_style(self, system_name: str, format_name: str, style_path: str):
     
     def add_mapping(self, system_name_source: str, system_name_target: str, mappings):
         """Add new classification system mapping."""
-        def get_id_by_name(name, classes):
-            """Get id of class."""
-            return list(filter(lambda x: x.name == name, classes))[0]['id']
-            
         _system_source_id = self._id(system_name_source)
         _system_target_id = self._id(system_name_target)
         
@@ -256,8 +276,8 @@ def get_id_by_name(name, classes):
         for i in mappings:
             if type(i['source_class_id']) != str:
                 break
-            i['source_class_id'] = get_id_by_name(i['source_class_id'], _system_source_id.classes)
-            i['target_class_id'] = get_id_by_name(i['target_class_id'], _system_target_id.classes)
+            i['source_class_id'] = Utils.get_id_by_name(i['source_class_id'], _system_source_id.classes)
+            i['target_class_id'] = Utils.get_id_by_name(i['target_class_id'], _system_target_id.classes)
 
         try:
             retval = Utils._post(url, json=mappings)
diff --git a/lccs/utils.py b/lccs/utils.py
index 257eaf2..c87f62e 100644
--- a/lccs/utils.py
+++ b/lccs/utils.py
@@ -80,3 +80,8 @@ def render_html(template_name, **kwargs):
         """Render Jinja2 HTML template."""
         template = templateEnv.get_template(template_name)
         return template.render(**kwargs)
+
+    @staticmethod
+    def get_id_by_name(name, classes):
+        """Get id of class."""
+        return list(filter(lambda x: x.name == name, classes))[0]['id']