diff --git a/sqlite_utils/db.py b/sqlite_utils/db.py
index 22cf02e..0858323 100644
--- a/sqlite_utils/db.py
+++ b/sqlite_utils/db.py
@@ -943,8 +943,6 @@ class Table(Queryable):
         data
         """
         pk = self.value_or_default("pk", pk)
-        if upsert and not pk:
-            raise PrimaryKeyRequired("upsert() requires a pk")
         foreign_keys = self.value_or_default("foreign_keys", foreign_keys)
         column_order = self.value_or_default("column_order", column_order)
         not_null = self.value_or_default("not_null", not_null)
@@ -957,7 +955,12 @@ class Table(Queryable):
         extracts = self.value_or_default("extracts", extracts)
         conversions = self.value_or_default("conversions", conversions)
 
+        if upsert and (not pk and not hash_id):
+            raise PrimaryKeyRequired("upsert() requires a pk")
         assert not (hash_id and pk), "Use either pk= or hash_id="
+        if hash_id:
+            pk = hash_id
+
         assert not (
             ignore and replace
         ), "Use either ignore=True or replace=True, not both"
diff --git a/tests/test_upsert.py b/tests/test_upsert.py
index 4d53fa8..584a496 100644
--- a/tests/test_upsert.py
+++ b/tests/test_upsert.py
@@ -28,6 +28,14 @@ def test_upsert_error_if_no_pk(fresh_db):
         table.upsert({"id": 1, "name": "Cleo"})
 
 
+def test_upsert_with_hash_id(fresh_db):
+    table = fresh_db["table"]
+    table.upsert({"foo": "bar"}, hash_id="pk")
+    assert [{"pk": "a5e744d0164540d33b1d7ea616c28f2fa97e754a", "foo": "bar"}] == list(
+        table.rows
+    )
+
+
 def test_upsert_compound_primary_key(fresh_db):
     table = fresh_db["table"]
     table.upsert_all(