diff --git a/Processor.php b/Processor.php
index 1b960bd..7290838 100644
--- a/Processor.php
+++ b/Processor.php
@@ -10,10 +10,12 @@
 class Processor
 {
     private $io;
+    private $isStarted;
 
     public function __construct(IOInterface $io)
     {
         $this->io = $io;
+        $this->isStarted = false;
     }
 
     public function processFile(array $config)
@@ -70,7 +72,7 @@ private function processConfig(array $config)
         }
 
         if (empty($config['dist-file'])) {
-            $config['dist-file'] = $config['file'].'.dist';
+            $config['dist-file'] = $config['file'] . '.dist';
         }
 
         if (!is_file($config['dist-file'])) {
@@ -141,27 +143,62 @@ private function getParams(array $expectedParams, array $actualParams)
     {
         // Simply use the expectedParams value as default for the missing params.
         if (!$this->io->isInteractive()) {
-            return array_replace($expectedParams, $actualParams);
+            return array_replace_recursive($expectedParams, $actualParams);
         }
 
-        $isStarted = false;
+        $actualParams = $this->provideParams($expectedParams, $actualParams);
 
-        foreach ($expectedParams as $key => $message) {
-            if (array_key_exists($key, $actualParams)) {
+        return $actualParams;
+    }
+
+    /**
+     * @param array  $expectedParams
+     * @param array  $actualParams
+     * @param string $parentKeys
+     *
+     * @return array
+     */
+    private function provideParams(array $expectedParams, array $actualParams, $parentKeys = '')
+    {
+        foreach ($expectedParams as $paramKey => $paramValue) {
+            if (array_key_exists($paramKey, $actualParams) && !is_array($paramValue)) {
                 continue;
             }
 
-            if (!$isStarted) {
-                $isStarted = true;
-                $this->io->write('<comment>Some parameters are missing. Please provide them.</comment>');
+            if (is_array($paramValue)) {
+                if (!array_key_exists($paramKey, $actualParams)) {
+                    $actualParams[$paramKey] = array();
+                }
+
+                $actualParams[$paramKey] = $this->provideParams($paramValue, $actualParams[$paramKey], $this->getParametersPath($parentKeys, $paramKey));
+            } else {
+                if (!$this->isStarted) {
+                    $this->isStarted = true;
+                    $this->io->write('<comment>Some parameters are missing. Please provide them.</comment>');
+                }
+
+                $default = Inline::dump($paramValue);
+                $parametersPath = $this->getParametersPath($parentKeys, $paramKey);
+                $value = $this->io->ask(
+                    sprintf('<question>%s</question> (<comment>%s</comment>): ', $parametersPath, $default),
+                    $default
+                );
+                $actualParams[$paramKey] = Inline::parse($value);
             }
 
-            $default = Inline::dump($message);
-            $value = $this->io->ask(sprintf('<question>%s</question> (<comment>%s</comment>): ', $key, $default), $default);
-
-            $actualParams[$key] = Inline::parse($value);
         }
 
         return $actualParams;
     }
+
+    /**
+     * @param $parentKeys
+     * @param $key
+     *
+     * @return string
+     */
+    private function getParametersPath($parentKeys, $key)
+    {
+        return $parentKeys ? $parentKeys . '.' . $key : $key;
+    }
 }
diff --git a/README.md b/README.md
index 0f42600..9711bbd 100644
--- a/README.md
+++ b/README.md
@@ -3,7 +3,8 @@
 This tool allows you to manage your ignored parameters when running a composer
 install or update. It works when storing the parameters in a Yaml file under
 a single top-level key (named ``parameters`` by default). Other keys are
-copied without change.
+copied without change. It's obviously possible to nest multi-level parameters
+in your Yaml file.
 
 [![Build Status](https://travis-ci.org/Incenteev/ParameterHandler.png)](https://travis-ci.org/Incenteev/ParameterHandler)
 [![Code Coverage](https://scrutinizer-ci.com/g/Incenteev/ParameterHandler/badges/coverage.png?s=ea5de28d9764fdcb6a576a41e244c0ac537b3c81)](https://scrutinizer-ci.com/g/Incenteev/ParameterHandler/)
diff --git a/Tests/fixtures/testcases/extra_array_keys/dist.yml b/Tests/fixtures/testcases/extra_array_keys/dist.yml
new file mode 100644
index 0000000..069d020
--- /dev/null
+++ b/Tests/fixtures/testcases/extra_array_keys/dist.yml
@@ -0,0 +1,10 @@
+parameters:
+    foo: bar
+    bare:
+        foo2: existing_foo2
+        foo3: existing_foo3
+        foo4: existing_foo4
+        foo5:
+            bare2:
+                - bloup
+                - glop
diff --git a/Tests/fixtures/testcases/extra_array_keys/existing.yml b/Tests/fixtures/testcases/extra_array_keys/existing.yml
new file mode 100644
index 0000000..6583f6f
--- /dev/null
+++ b/Tests/fixtures/testcases/extra_array_keys/existing.yml
@@ -0,0 +1,6 @@
+# This file is auto-generated during the composer install
+parameters:
+    foo: existing_foo
+    bare:
+        foo1: existing_foo1
+        foo3: existing_foo3
diff --git a/Tests/fixtures/testcases/extra_array_keys/expected.yml b/Tests/fixtures/testcases/extra_array_keys/expected.yml
new file mode 100644
index 0000000..30c3457
--- /dev/null
+++ b/Tests/fixtures/testcases/extra_array_keys/expected.yml
@@ -0,0 +1,12 @@
+# This file is auto-generated during the composer install
+parameters:
+    foo: existing_foo
+    bare:
+        foo2: existing_foo2
+        foo3: existing_foo3
+        foo4: existing_foo4
+        foo5:
+            bare2:
+                - bloup
+                - glop
+        foo1: existing_foo1
diff --git a/Tests/fixtures/testcases/extra_array_keys/setup.yml b/Tests/fixtures/testcases/extra_array_keys/setup.yml
new file mode 100644
index 0000000..726a209
--- /dev/null
+++ b/Tests/fixtures/testcases/extra_array_keys/setup.yml
@@ -0,0 +1 @@
+title: Extra deep array keys and preserve existing values