diff --git a/src/Symfony/Bundle/FrameworkBundle/Resources/config/schema/symfony-1.0.xsd b/src/Symfony/Bundle/FrameworkBundle/Resources/config/schema/symfony-1.0.xsd
index 0a7a56f675a65..5931d1261bd53 100644
--- a/src/Symfony/Bundle/FrameworkBundle/Resources/config/schema/symfony-1.0.xsd
+++ b/src/Symfony/Bundle/FrameworkBundle/Resources/config/schema/symfony-1.0.xsd
@@ -571,11 +571,16 @@
 
     <xsd:complexType name="mailer">
         <xsd:sequence>
+            <xsd:element name="transport" type="mailer_transport" minOccurs="0" maxOccurs="unbounded" />
             <xsd:element name="envelope" type="mailer_envelope" minOccurs="0" maxOccurs="1" />
         </xsd:sequence>
         <xsd:attribute name="dsn" type="xsd:string" />
     </xsd:complexType>
 
+    <xsd:complexType name="mailer_transport" mixed="true">
+        <xsd:attribute name="name" type="xsd:string" use="required" />
+    </xsd:complexType>
+
     <xsd:complexType name="mailer_envelope">
         <xsd:sequence>
             <xsd:element name="sender" type="xsd:string" minOccurs="0" maxOccurs="1" />
diff --git a/src/Symfony/Bundle/FrameworkBundle/Tests/DependencyInjection/Fixtures/php/mailer_with_dsn.php b/src/Symfony/Bundle/FrameworkBundle/Tests/DependencyInjection/Fixtures/php/mailer_with_dsn.php
new file mode 100644
index 0000000000000..7eec06a9a0e50
--- /dev/null
+++ b/src/Symfony/Bundle/FrameworkBundle/Tests/DependencyInjection/Fixtures/php/mailer_with_dsn.php
@@ -0,0 +1,15 @@
+<?php
+
+namespace Symfony\Component\DependencyInjection\Loader\Configurator;
+
+return static function (ContainerConfigurator $container) {
+    $container->extension('framework', [
+        'mailer' => [
+            'dsn' => 'smtp://example.com',
+            'envelope' => [
+                'sender' => 'sender@example.org',
+                'recipients' => ['redirected@example.org', 'redirected1@example.org'],
+            ],
+        ],
+    ]);
+};
diff --git a/src/Symfony/Bundle/FrameworkBundle/Tests/DependencyInjection/Fixtures/php/mailer_with_transports.php b/src/Symfony/Bundle/FrameworkBundle/Tests/DependencyInjection/Fixtures/php/mailer_with_transports.php
new file mode 100644
index 0000000000000..1bc79f3dd204c
--- /dev/null
+++ b/src/Symfony/Bundle/FrameworkBundle/Tests/DependencyInjection/Fixtures/php/mailer_with_transports.php
@@ -0,0 +1,18 @@
+<?php
+
+namespace Symfony\Component\DependencyInjection\Loader\Configurator;
+
+return static function (ContainerConfigurator $container) {
+    $container->extension('framework', [
+        'mailer' => [
+            'transports' => [
+                'transport1' => 'smtp://example1.com',
+                'transport2' => 'smtp://example2.com',
+            ],
+            'envelope' => [
+                'sender' => 'sender@example.org',
+                'recipients' => ['redirected@example.org', 'redirected1@example.org'],
+            ],
+        ],
+    ]);
+};
diff --git a/src/Symfony/Bundle/FrameworkBundle/Tests/DependencyInjection/Fixtures/xml/mailer.xml b/src/Symfony/Bundle/FrameworkBundle/Tests/DependencyInjection/Fixtures/xml/mailer_with_dsn.xml
similarity index 100%
rename from src/Symfony/Bundle/FrameworkBundle/Tests/DependencyInjection/Fixtures/xml/mailer.xml
rename to src/Symfony/Bundle/FrameworkBundle/Tests/DependencyInjection/Fixtures/xml/mailer_with_dsn.xml
diff --git a/src/Symfony/Bundle/FrameworkBundle/Tests/DependencyInjection/Fixtures/xml/mailer_with_transports.xml b/src/Symfony/Bundle/FrameworkBundle/Tests/DependencyInjection/Fixtures/xml/mailer_with_transports.xml
new file mode 100644
index 0000000000000..a6eb67dc81024
--- /dev/null
+++ b/src/Symfony/Bundle/FrameworkBundle/Tests/DependencyInjection/Fixtures/xml/mailer_with_transports.xml
@@ -0,0 +1,20 @@
+<?xml version="1.0" ?>
+
+<container xmlns="http://symfony.com/schema/dic/services"
+           xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+           xmlns:framework="http://symfony.com/schema/dic/symfony"
+           xsi:schemaLocation="http://symfony.com/schema/dic/services https://symfony.com/schema/dic/services/services-1.0.xsd
+                        http://symfony.com/schema/dic/symfony https://symfony.com/schema/dic/symfony/symfony-1.0.xsd">
+
+    <framework:config>
+        <framework:mailer>
+            <framework:transport name="transport1">smtp://example1.com</framework:transport>
+            <framework:transport name="transport2">smtp://example2.com</framework:transport>
+            <framework:envelope>
+                <framework:sender>sender@example.org</framework:sender>
+                <framework:recipients>redirected@example.org</framework:recipients>
+                <framework:recipients>redirected1@example.org</framework:recipients>
+            </framework:envelope>
+        </framework:mailer>
+    </framework:config>
+</container>
diff --git a/src/Symfony/Bundle/FrameworkBundle/Tests/DependencyInjection/Fixtures/yml/mailer.yml b/src/Symfony/Bundle/FrameworkBundle/Tests/DependencyInjection/Fixtures/yml/mailer_with_dsn.yml
similarity index 100%
rename from src/Symfony/Bundle/FrameworkBundle/Tests/DependencyInjection/Fixtures/yml/mailer.yml
rename to src/Symfony/Bundle/FrameworkBundle/Tests/DependencyInjection/Fixtures/yml/mailer_with_dsn.yml
diff --git a/src/Symfony/Bundle/FrameworkBundle/Tests/DependencyInjection/Fixtures/yml/mailer_with_transports.yml b/src/Symfony/Bundle/FrameworkBundle/Tests/DependencyInjection/Fixtures/yml/mailer_with_transports.yml
new file mode 100644
index 0000000000000..6035988d76e59
--- /dev/null
+++ b/src/Symfony/Bundle/FrameworkBundle/Tests/DependencyInjection/Fixtures/yml/mailer_with_transports.yml
@@ -0,0 +1,10 @@
+framework:
+    mailer:
+        transports:
+            transport1: 'smtp://example1.com'
+            transport2: 'smtp://example2.com'
+        envelope:
+            sender: sender@example.org
+            recipients:
+                - redirected@example.org
+                - redirected1@example.org
diff --git a/src/Symfony/Bundle/FrameworkBundle/Tests/DependencyInjection/FrameworkExtensionTest.php b/src/Symfony/Bundle/FrameworkBundle/Tests/DependencyInjection/FrameworkExtensionTest.php
index 73cc81c480a1a..1bc157079c549 100644
--- a/src/Symfony/Bundle/FrameworkBundle/Tests/DependencyInjection/FrameworkExtensionTest.php
+++ b/src/Symfony/Bundle/FrameworkBundle/Tests/DependencyInjection/FrameworkExtensionTest.php
@@ -1617,13 +1617,29 @@ public function testHttpClientFullDefaultOptions()
         ], $defaultOptions['peer_fingerprint']);
     }
 
-    public function testMailer(): void
+    public function provideMailer(): array
+    {
+        return [
+            ['mailer_with_dsn', ['main' => 'smtp://example.com']],
+            ['mailer_with_transports', [
+                'transport1' => 'smtp://example1.com',
+                'transport2' => 'smtp://example2.com',
+            ]],
+        ];
+    }
+
+    /**
+     * @dataProvider provideMailer
+     */
+    public function testMailer(string $configFile, array $expectedTransports): void
     {
-        $container = $this->createContainerFromFile('mailer');
+        $container = $this->createContainerFromFile($configFile);
 
         $this->assertTrue($container->hasAlias('mailer'));
+        $this->assertTrue($container->hasDefinition('mailer.transports'));
+        $this->assertSame($expectedTransports, $container->getDefinition('mailer.transports')->getArgument(0));
         $this->assertTrue($container->hasDefinition('mailer.default_transport'));
-        $this->assertSame('smtp://example.com', $container->getDefinition('mailer.default_transport')->getArgument(0));
+        $this->assertSame(current($expectedTransports), $container->getDefinition('mailer.default_transport')->getArgument(0));
         $this->assertTrue($container->hasDefinition('mailer.envelope_listener'));
         $l = $container->getDefinition('mailer.envelope_listener');
         $this->assertSame('sender@example.org', $l->getArgument(0));