diff --git a/src/Frontend/Accounts/AccountController.php b/src/Frontend/Accounts/AccountController.php
index 7209067..4a6e268 100644
--- a/src/Frontend/Accounts/AccountController.php
+++ b/src/Frontend/Accounts/AccountController.php
@@ -6,6 +6,7 @@ namespace MailAccountAdmin\Frontend\Accounts;
 use MailAccountAdmin\Common\ActionResult;
 use MailAccountAdmin\Common\SessionHelper;
 use MailAccountAdmin\Common\UserHelper;
+use MailAccountAdmin\Exceptions\AccountNotFoundException;
 use MailAccountAdmin\Exceptions\AppException;
 use MailAccountAdmin\Exceptions\InputValidationError;
 use MailAccountAdmin\Frontend\BaseController;
@@ -24,6 +25,14 @@ class AccountController extends BaseController
     }
 
 
+    // -- Error pages
+
+    public function showAccount404(Response $response, int $accountId): Response
+    {
+        return $this->view->render($response, 'account_404.html.twig', ['id' => $accountId])->withStatus(404);
+    }
+
+
     // -- /accounts - List all accounts
 
     public function showAccounts(Request $request, Response $response): Response
@@ -49,7 +58,12 @@ class AccountController extends BaseController
         // Parse URL arguments
         $accountId = (int)$args['id'];
 
-        $renderData = $this->accountHandler->getAccountDetails($accountId);
+        try {
+            $renderData = $this->accountHandler->getAccountDetails($accountId);
+        } catch (AccountNotFoundException $e) {
+            return $this->showAccount404($response, $accountId);
+        }
+
         return $this->view->render($response, 'account_details.html.twig', $renderData);
     }
 
@@ -99,8 +113,12 @@ class AccountController extends BaseController
         // Parse URL arguments
         $accountId = (int)$args['id'];
 
-        // Get account data from database
-        $renderData = $this->accountHandler->getAccountDataForEdit($accountId);
+        try {
+            // Get account data from database
+            $renderData = $this->accountHandler->getAccountDataForEdit($accountId);
+        } catch (AccountNotFoundException $e) {
+            return $this->showAccount404($response, $accountId);
+        }
 
         // If the form has been submitted, add the result message and form input data to the render data array
         $renderData = $this->addLastActionResultToRenderData($renderData);
@@ -142,8 +160,12 @@ class AccountController extends BaseController
         // Parse URL arguments
         $accountId = (int)$args['id'];
 
-        // Get account data and list of aliases from database
-        $renderData = $this->accountHandler->getAccountDataForDelete($accountId);
+        try {
+            // Get account data and list of aliases from database
+            $renderData = $this->accountHandler->getAccountDataForDelete($accountId);
+        } catch (AccountNotFoundException $e) {
+            return $this->showAccount404($response, $accountId);
+        }
 
         // If the form has been submitted, add the result message to the render data array
         $renderData = $this->addLastActionResultToRenderData($renderData);
diff --git a/templates/account_404.html.twig b/templates/account_404.html.twig
new file mode 100644
index 0000000..5c17302
--- /dev/null
+++ b/templates/account_404.html.twig
@@ -0,0 +1,14 @@
+{% extends "base.html.twig" %}
+
+{% block title %}Account not found{% endblock %}
+
+{% block content %}
+    <h2>Account not found</h2>
+
+    <div class="error_box">
+        <h4>Error</h4>
+        <p>The account with the ID {{ id }} was not found.</p>
+    </div>
+
+    <p>Go back to <a href="/accounts">account list</a>.</p>
+{% endblock %}