diff --git a/src/prefixmaps/data/linked_data.csv b/src/prefixmaps/data/linked_data.csv
index 041d713..8694c79 100644
--- a/src/prefixmaps/data/linked_data.csv
+++ b/src/prefixmaps/data/linked_data.csv
@@ -12,6 +12,7 @@ linkml,odrl,http://www.w3.org/ns/odrl/2/,canonical
 linkml,oslc,http://open-services.net/ns/core#,canonical
 linkml,owl,http://www.w3.org/2002/07/owl#,canonical
 linkml,pav,http://purl.org/pav/,canonical
+linkml,PHENOTYPE,https://w3id.org/monarch-initiative/entity/PHENOTYPE_,canonical
 linkml,prov,http://www.w3.org/ns/prov#,canonical
 linkml,qb,http://purl.org/linked-data/cube#,canonical
 linkml,qudt,http://qudt.org/schema/qudt/,canonical
diff --git a/src/prefixmaps/data/linked_data.curated.yaml b/src/prefixmaps/data/linked_data.curated.yaml
index e04cb68..7718246 100644
--- a/src/prefixmaps/data/linked_data.curated.yaml
+++ b/src/prefixmaps/data/linked_data.curated.yaml
@@ -33,3 +33,6 @@ prefixes:
   dcmitype: http://purl.org/dc/dcmitype/
   wgs: http://www.w3.org/2003/01/geo/wgs84_pos#
   xml: http://www.w3.org/XML/1998/namespace
+  # Phenotype classes minted by uphenotizer and imported by PHENIO
+  # (https://github.com/monarch-initiative/uphenotizer)
+  PHENOTYPE: https://w3id.org/monarch-initiative/entity/PHENOTYPE_
diff --git a/src/prefixmaps/data/merged.csv b/src/prefixmaps/data/merged.csv
index 6c3de9d..caac1cb 100644
--- a/src/prefixmaps/data/merged.csv
+++ b/src/prefixmaps/data/merged.csv
@@ -12121,6 +12121,7 @@ merged,PHENOLEXPLORER,https://identifiers.org/phenolexplorer/,prefix_alias,biore
 merged,PHENOLEXPLORER,https://identifiers.org/phenolexplorer:,prefix_alias,bioregistry
 merged,PHENOLEXPLORER,https://n2t.net/phenolexplorer:,prefix_alias,bioregistry
 merged,PHENOLEXPLORER,https://phenol-explorer.eu/foods/,prefix_alias,bioregistry
+merged,PHENOTYPE,https://w3id.org/monarch-initiative/entity/PHENOTYPE_,canonical,linkml
 merged,PHENX,https://www.phenxtoolkit.org/protocols/view/,canonical,bioregistry
 merged,PHENX,http://bioregistry.io/phenx:,prefix_alias,bioregistry
 merged,PHENX,http://bioregistry.io/phenxtoolkit:,prefix_alias,bioregistry
diff --git a/src/prefixmaps/data/merged.monarch.csv b/src/prefixmaps/data/merged.monarch.csv
index b87346c..e74c372 100644
--- a/src/prefixmaps/data/merged.monarch.csv
+++ b/src/prefixmaps/data/merged.monarch.csv
@@ -12121,6 +12121,7 @@ merged.monarch,PHENOLEXPLORER,https://identifiers.org/phenolexplorer/,prefix_ali
 merged.monarch,PHENOLEXPLORER,https://identifiers.org/phenolexplorer:,prefix_alias,bioregistry
 merged.monarch,PHENOLEXPLORER,https://n2t.net/phenolexplorer:,prefix_alias,bioregistry
 merged.monarch,PHENOLEXPLORER,https://phenol-explorer.eu/foods/,prefix_alias,bioregistry
+merged.monarch,PHENOTYPE,https://w3id.org/monarch-initiative/entity/PHENOTYPE_,canonical,linkml
 merged.monarch,PHENX,https://www.phenxtoolkit.org/protocols/view/,canonical,bioregistry
 merged.monarch,PHENX,http://bioregistry.io/phenx:,prefix_alias,bioregistry
 merged.monarch,PHENX,http://bioregistry.io/phenxtoolkit:,prefix_alias,bioregistry
diff --git a/src/prefixmaps/data/merged.oak.csv b/src/prefixmaps/data/merged.oak.csv
index 6a45ae8..93c471b 100644
--- a/src/prefixmaps/data/merged.oak.csv
+++ b/src/prefixmaps/data/merged.oak.csv
@@ -12121,6 +12121,7 @@ merged.oak,PHENOLEXPLORER,https://identifiers.org/phenolexplorer/,prefix_alias,b
 merged.oak,PHENOLEXPLORER,https://identifiers.org/phenolexplorer:,prefix_alias,bioregistry
 merged.oak,PHENOLEXPLORER,https://n2t.net/phenolexplorer:,prefix_alias,bioregistry
 merged.oak,PHENOLEXPLORER,https://phenol-explorer.eu/foods/,prefix_alias,bioregistry
+merged.oak,PHENOTYPE,https://w3id.org/monarch-initiative/entity/PHENOTYPE_,canonical,linkml
 merged.oak,PHENX,https://www.phenxtoolkit.org/protocols/view/,canonical,bioregistry
 merged.oak,PHENX,http://bioregistry.io/phenx:,prefix_alias,bioregistry
 merged.oak,PHENX,http://bioregistry.io/phenxtoolkit:,prefix_alias,bioregistry
diff --git a/tests/test_core/test_prefixmaps.py b/tests/test_core/test_prefixmaps.py
index 565a2c9..dc7107b 100644
--- a/tests/test_core/test_prefixmaps.py
+++ b/tests/test_core/test_prefixmaps.py
@@ -229,3 +229,13 @@ def test_synonyms(self):
         for curie in others:
             with self.subTest(curie=curie):
                 self.assertEqual(canonical, converter.standardize_curie(curie))
+
+    def test_curated_phenotype_prefix(self):
+        """PHENOTYPE is curated in linked_data, so it reaches every merged context."""
+        curie = "PHENOTYPE:1001742"
+        uri = "https://w3id.org/monarch-initiative/entity/PHENOTYPE_1001742"
+        for name in ["linked_data", "merged", "merged.monarch", "merged.oak"]:
+            with self.subTest(context=name):
+                converter = prefixmaps.load_converter(name)
+                self.assertEqual(uri, converter.expand(curie))
+                self.assertEqual(curie, converter.compress(uri))