diff --git a/oslo_service/service.py b/oslo_service/service.py
index fa9c37c2..107a5ddb 100644
--- a/oslo_service/service.py
+++ b/oslo_service/service.py
@@ -34,6 +34,7 @@ import time
 
 import eventlet
 from eventlet import event
+from eventlet import tpool
 
 from oslo_concurrency import lockutils
 from oslo_service._i18n import _
@@ -560,6 +561,9 @@ class ProcessLauncher(object):
 
         pid = os.fork()
         if pid == 0:
+            # When parent used native threads the library on child needs to be
+            # "reset", otherwise native threads won't work on the child.
+            tpool.killall()
             self.launcher = self._child_process(wrap.service)
             while True:
                 self._child_process_handle_signal()
diff --git a/releasenotes/notes/native-threads-on-child-7150690c7caa1013.yaml b/releasenotes/notes/native-threads-on-child-7150690c7caa1013.yaml
new file mode 100644
index 00000000..a6525639
--- /dev/null
+++ b/releasenotes/notes/native-threads-on-child-7150690c7caa1013.yaml
@@ -0,0 +1,8 @@
+---
+fixes:
+  - |
+    `Bug #1983949
+    <https://bugs.launchpad.net/oslo.service/+bug/1983949>`_: Fixed eventlet
+    native threads tpool on child process when parent process has used them
+    before launching the service.
+