diff --git a/src/LightSaml/Logout/Action/Profile/Outbound/LogoutRequest/ResolveLogoutPartyAction.php b/src/LightSaml/Logout/Action/Profile/Outbound/LogoutRequest/ResolveLogoutPartyAction.php
index 7476cec..cc4672e 100644
--- a/src/LightSaml/Logout/Action/Profile/Outbound/LogoutRequest/ResolveLogoutPartyAction.php
+++ b/src/LightSaml/Logout/Action/Profile/Outbound/LogoutRequest/ResolveLogoutPartyAction.php
@@ -93,6 +93,6 @@ private function findParty($entityId, array $entityDescriptorStores)
             }
         }
 
-        return null;
+        return;
     }
 }
diff --git a/src/LightSaml/Logout/Action/Profile/Outbound/LogoutRequest/SetSessionIndexAction.php b/src/LightSaml/Logout/Action/Profile/Outbound/LogoutRequest/SetSessionIndexAction.php
new file mode 100644
index 0000000..18f7824
--- /dev/null
+++ b/src/LightSaml/Logout/Action/Profile/Outbound/LogoutRequest/SetSessionIndexAction.php
@@ -0,0 +1,33 @@
+<?php
+
+/*
+ * This file is part of the LightSAML-Logout package.
+ *
+ * (c) Milos Tomic <tmilos@lightsaml.com>
+ *
+ * This source file is subject to the GPL-3 license that is bundled
+ * with this source code in the file LICENSE.
+ */
+
+namespace LightSaml\Logout\Action\Profile\Outbound\LogoutRequest;
+
+use LightSaml\Action\Profile\AbstractProfileAction;
+use LightSaml\Context\Profile\Helper\MessageContextHelper;
+use LightSaml\Context\Profile\ProfileContext;
+
+/**
+ * Sets SessionIndex of the outbounding AuthnRequest with values given in the LogoutContext SsoSessionState.
+ */
+class SetSessionIndexAction extends AbstractProfileAction
+{
+    /**
+     * @param ProfileContext $context
+     */
+    protected function doExecute(ProfileContext $context)
+    {
+        $logoutRequest = MessageContextHelper::asLogoutRequest($context->getOutboundContext());
+        $ssoSessionState = $context->getLogoutSsoSessionState();
+
+        $logoutRequest->setSessionIndex($ssoSessionState->getSessionIndex());
+    }
+}
diff --git a/src/LightSaml/Logout/Builder/Action/Profile/SingleLogout/SloRequestActionBuilder.php b/src/LightSaml/Logout/Builder/Action/Profile/SingleLogout/SloRequestActionBuilder.php
index a712550..c51ee83 100644
--- a/src/LightSaml/Logout/Builder/Action/Profile/SingleLogout/SloRequestActionBuilder.php
+++ b/src/LightSaml/Logout/Builder/Action/Profile/SingleLogout/SloRequestActionBuilder.php
@@ -19,6 +19,7 @@
 use LightSaml\Logout\Action\Profile\Outbound\LogoutRequest\ResolveLogoutPartyAction;
 use LightSaml\Logout\Action\Profile\Outbound\LogoutRequest\SetNameIdAction;
 use LightSaml\Logout\Action\Profile\Outbound\LogoutRequest\SetNotOnOrAfterAction;
+use LightSaml\Logout\Action\Profile\Outbound\LogoutRequest\SetSessionIndexAction;
 use LightSaml\Action\Profile\Outbound\Message\MessageIdAction;
 use LightSaml\Action\Profile\Outbound\Message\MessageIssueInstantAction;
 use LightSaml\Action\Profile\Outbound\Message\MessageVersionAction;
@@ -31,7 +32,6 @@
 class SloRequestActionBuilder extends AbstractProfileActionBuilder
 {
     /**
-     * @return void
      */
     protected function doInitialize()
     {
@@ -69,6 +69,9 @@ protected function doInitialize()
         $proceedActionBuilder->add(new SetNameIdAction(
             $this->buildContainer->getSystemContainer()->getLogger()
         ));
+        $proceedActionBuilder->add(new SetSessionIndexAction(
+            $this->buildContainer->getSystemContainer()->getLogger()
+        ));
         $proceedActionBuilder->add(new SetNotOnOrAfterAction(
             $this->buildContainer->getSystemContainer()->getLogger(),
             $this->buildContainer->getSystemContainer()->getTimeProvider(),