diff --git a/CHANGES.md b/CHANGES.md
index 740ad80..ea55b5c 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -4,6 +4,10 @@
 
 * Add `create_products_as_new_nodes` strategy
 
+### 0.9.DEV38 (2024-09-12)
+
+* Fix #274: correctly set units for namespaced methods when importing ecoinvent with ecoinvent_interface
+
 ### 0.9.DEV37 (2024-09-04)
 
 * Fix out of order but with `create_randonneur_excel_template_for_unlinked`
diff --git a/bw2io/__init__.py b/bw2io/__init__.py
index e28e4a7..a557dbc 100644
--- a/bw2io/__init__.py
+++ b/bw2io/__init__.py
@@ -48,7 +48,7 @@
     "useeio20",
 ]
 
-__version__ = "0.9.DEV37"
+__version__ = "0.9.DEV38"
 
 from .backup import (
     backup_data_directory,
diff --git a/bw2io/ecoinvent.py b/bw2io/ecoinvent.py
index e8ad978..8ca472a 100644
--- a/bw2io/ecoinvent.py
+++ b/bw2io/ecoinvent.py
@@ -294,10 +294,21 @@ def import_ecoinvent_release(
         }
         cf_col_label = CF_COLUMN_LABELS.get(version, "cf")
         units_col_label = pick_a_unit_label_already(units[0])
-        units_mapping = {
-            (row["method"], row["category"], row["indicator"]): row[units_col_label]
-            for row in units
-        }
+        if namespace_lcia_methods:
+            units_mapping = {
+                (
+                    f"ecoinvent-{version}",
+                    row["method"],
+                    row["category"],
+                    row["indicator"],
+                ): row[units_col_label]
+                for row in units
+            }
+        else:
+            units_mapping = {
+                (row["method"], row["category"], row["indicator"]): row[units_col_label]
+                for row in units
+            }
 
         biosphere_mapping = {}
         for flow in bd.Database(biosphere_name):