diff --git a/patroni/postgresql.py b/patroni/postgresql.py
index 185b5caf..4ce4cc51 100644
--- a/patroni/postgresql.py
+++ b/patroni/postgresql.py
@@ -1181,9 +1181,12 @@ $$""".format(name, ' '.join(options)), name, password, password)
 
                 # drop unused slots
                 for slot in set(self._replication_slots) - slots:
-                    self._query("""SELECT pg_drop_replication_slot(%s)
-                                    WHERE EXISTS(SELECT 1 FROM pg_replication_slots
-                                    WHERE slot_name = %s AND NOT active)""", slot, slot)
+                    cursor = self._query("""SELECT pg_drop_replication_slot(%s)
+                                             WHERE EXISTS(SELECT 1 FROM pg_replication_slots
+                                             WHERE slot_name = %s AND NOT active)""", slot, slot)
+
+                    if cursor.rowcount != 1:  # Either slot doesn't exists or it is still active
+                        self._schedule_load_slots = True  # schedule load_replication_slots on the next iteration
 
                 # create new slots
                 for slot in slots - set(self._replication_slots):
diff --git a/tests/test_postgresql.py b/tests/test_postgresql.py
index 7f83b909..4481cb7e 100644
--- a/tests/test_postgresql.py
+++ b/tests/test_postgresql.py
@@ -19,6 +19,7 @@ class MockCursor(object):
     def __init__(self, connection):
         self.connection = connection
         self.closed = False
+        self.rowcount = 0
         self.results = []
 
     def execute(self, sql, *params):