diff --git a/src/Composer/Command/InitCommand.php b/src/Composer/Command/InitCommand.php
index 4c5871034..f21be1937 100644
--- a/src/Composer/Command/InitCommand.php
+++ b/src/Composer/Command/InitCommand.php
@@ -159,6 +159,8 @@ EOT
 
         if (!$name = $input->getOption('name')) {
             $name = basename($cwd);
+            $name = preg_replace('{(?:([a-z])([A-Z])|([A-Z])([A-Z][a-z]))}', '\\1\\3-\\2\\4', $name);
+            $name = strtolower($name);
             if (isset($git['github.user'])) {
                 $name = $git['github.user'] . '/' . $name;
             } elseif (!empty($_SERVER['USERNAME'])) {
@@ -169,6 +171,12 @@ EOT
                 // package names must be in the format foo/bar
                 $name = $name . '/' . $name;
             }
+        } else {
+            if (!preg_match('{^[a-z0-9_.-]+/[a-z0-9_.-]+$}', $name)) {
+                throw new \InvalidArgumentException(
+                    'The package name '.$name.' is invalid, it should be lowercase and have a vendor name, a forward slash, and a package name, matching: [a-z0-9_.-]+/[a-z0-9_.-]+'
+                );
+            }
         }
 
         $name = $dialog->askAndValidate(
@@ -179,9 +187,9 @@ EOT
                     return $name;
                 }
 
-                if (!preg_match('{^[a-z0-9_.-]+/[a-z0-9_.-]+$}i', $value)) {
+                if (!preg_match('{^[a-z0-9_.-]+/[a-z0-9_.-]+$}', $value)) {
                     throw new \InvalidArgumentException(
-                        'The package name '.$value.' is invalid, it should have a vendor name, a forward slash, and a package name, matching: [a-z0-9_.-]+/[a-z0-9_.-]+'
+                        'The package name '.$value.' is invalid, it should be lowercase and have a vendor name, a forward slash, and a package name, matching: [a-z0-9_.-]+/[a-z0-9_.-]+'
                     );
                 }