diff --git a/constructor/construct.py b/constructor/construct.py
index 1de1dd1ef..def261269 100644
--- a/constructor/construct.py
+++ b/constructor/construct.py
@@ -10,9 +10,10 @@
 from functools import partial
 from os.path import dirname
 
-from ruamel import yaml
+from ruamel.yaml import YAMLError
 
 from constructor.exceptions import UnableToParse, UnableToParseMissingJinja2, YamlParsingError
+from constructor.utils import yaml
 
 # list of tuples (key name, required, type, description)
 KEYS = [
@@ -694,8 +695,8 @@ def select_lines(data, namespace):
 def yamlize(data, directory, content_filter):
     data = content_filter(data)
     try:
-        return yaml.safe_load(data)
-    except yaml.error.YAMLError as e:
+        return yaml.load(data)
+    except YAMLError as e:
         if ('{{' not in data) and ('{%' not in data):
             raise UnableToParse(original=e)
         try:
@@ -703,7 +704,7 @@ def yamlize(data, directory, content_filter):
         except ImportError as ex:
             raise UnableToParseMissingJinja2(original=ex)
         data = render_jinja(data, directory, content_filter)
-        return yaml.load(data, Loader=yaml.SafeLoader)
+        return yaml.load(data)
 
 
 def parse(path, platform):
diff --git a/constructor/utils.py b/constructor/utils.py
index 09a96f2eb..395fa0841 100644
--- a/constructor/utils.py
+++ b/constructor/utils.py
@@ -9,14 +9,18 @@
 import math
 import re
 import sys
+from io import StringIO
 from os import sep, unlink
 from os.path import basename, isdir, isfile, islink, join, normpath
 from shutil import rmtree
 from subprocess import check_call, check_output
 
-from ruamel import yaml
+from ruamel.yaml import YAML
 
 logger = logging.getLogger(__name__)
+yaml = YAML(typ="rt")
+yaml.default_flow_style = False
+yaml.indent(mapping=2, sequence=4, offset=2)
 
 
 def explained_check_call(args):
@@ -35,6 +39,12 @@ def filename_dist(dist):
         return dist
 
 
+def yaml_to_string(data):
+    blob = StringIO()
+    yaml.dump(data, blob)
+    return blob.getvalue()
+
+
 def fill_template(data, d, exceptions=[]):
     pat = re.compile(r'__(\w+)__')
 
@@ -117,7 +127,7 @@ def add_condarc(info):
         if channel_alias:
             condarc['channel_alias'] = channel_alias
     if isinstance(condarc, dict):
-        condarc = yaml.dump(condarc, default_flow_style=False)
+        condarc = yaml_to_string(condarc)
     yield '# ----- add condarc'
     if info['_platform'].startswith('win'):
         yield 'Var /Global CONDARC'
diff --git a/dev/environment.yml b/dev/environment.yml
index ba74a8fd6..50a2b25d1 100644
--- a/dev/environment.yml
+++ b/dev/environment.yml
@@ -4,6 +4,6 @@ channels:
 dependencies:
   - python
   - conda >=4.6
-  - ruamel.yaml >=0.11.14,<0.18
+  - ruamel.yaml >=0.11.14,<0.19
   - conda-standalone # >=23.11.0
   - pillow >=3.1  # [osx or win]
diff --git a/news/739-ruamel-yaml b/news/739-ruamel-yaml
new file mode 100644
index 000000000..eb7a044f5
--- /dev/null
+++ b/news/739-ruamel-yaml
@@ -0,0 +1,19 @@
+### Enhancements
+
+* Add support for `ruamel.yaml` 0.18 API. (#729 via #739)
+
+### Bug fixes
+
+* <news item>
+
+### Deprecations
+
+* <news item>
+
+### Docs
+
+* <news item>
+
+### Other
+
+* <news item>
diff --git a/recipe/meta.yaml b/recipe/meta.yaml
index 77fd8f994..702ca535d 100644
--- a/recipe/meta.yaml
+++ b/recipe/meta.yaml
@@ -22,7 +22,7 @@ requirements:
   run:
     - conda >=4.6
     - python
-    - ruamel.yaml >=0.11.14,<0.18
+    - ruamel.yaml >=0.11.14,<0.19
     - conda-standalone
     - pillow >=3.1     # [win or osx]
     - nsis >=3.08      # [win]
diff --git a/setup.py b/setup.py
index 022ec64c4..9bb529441 100644
--- a/setup.py
+++ b/setup.py
@@ -24,7 +24,7 @@
     },
     install_requires=[
         "conda >=4.6",
-        "ruamel.yaml >=0.11.14,<0.18",
+        "ruamel.yaml >=0.11.14,<0.19",
         "pillow >=3.1 ; platform_system=='Windows' or platform_system=='Darwin'",
         # non-python dependency: "nsis >=3.08 ; platform_system=='Windows'",
     ],