Index: wp-includes/functions.php
===================================================================
--- wp-includes/functions.php	(revision 12593)
+++ wp-includes/functions.php	(working copy)
@@ -2251,12 +2251,13 @@
 	$ext2type = apply_filters( 'ext2type', array(
 		'audio'       => array( 'aac', 'ac3',  'aif',  'aiff', 'm3a',  'm4a',   'm4b', 'mka', 'mp1',  'mp2', 'mp3', 'ogg', 'ram', 'wav', 'wma' ),
 		'video'       => array( 'asf', 'avi',  'divx', 'dv',   'flv',  'mkv',   'mov', 'mpg', 'mpeg', 'mp4', 'mpv', 'ogm', 'qt',  'rm', 'vob', 'wmv', 'm4v' ),
-		'document'    => array( 'doc', 'docx', 'docm', 'dotm', 'odt',  'pages', 'pdf', 'rtf' ),
+		'document'    => array( 'doc', 'docx', 'docm', 'dotm', 'odt',  'pages', 'rtf' ),
 		'spreadsheet' => array( 'numbers',     'ods',  'xls',  'xlsx', 'xlsb',  'xlsm' ),
 		'interactive' => array( 'key', 'ppt',  'pptx', 'pptm', 'odp',  'swf' ),
 		'text'        => array( 'asc', 'txt' ),
 		'archive'     => array( 'bz2', 'cab',  'dmg',  'gz',   'rar',  'sea',   'sit', 'sqx', 'tar', 'tgz', 'zip' ),
 		'code'        => array( 'css', 'html', 'php',  'js' ),
+		'pdf'		  => array( 'pdf' ),
 	));
 	foreach ( $ext2type as $type => $exts )
 		if ( in_array( $ext, $exts ) )
Index: wp-admin/includes/post.php
===================================================================
--- wp-admin/includes/post.php	(revision 12593)
+++ wp-admin/includes/post.php	(working copy)
@@ -868,6 +868,7 @@
 		'image' => array(__('Images'), __('Manage Images'), _n_noop('Image <span class="count">(%s)</span>', 'Images <span class="count">(%s)</span>')),
 		'audio' => array(__('Audio'), __('Manage Audio'), _n_noop('Audio <span class="count">(%s)</span>', 'Audio <span class="count">(%s)</span>')),
 		'video' => array(__('Video'), __('Manage Video'), _n_noop('Video <span class="count">(%s)</span>', 'Video <span class="count">(%s)</span>')),
+		'application/pdf' => array(__('PDFs'), __('Manage PDFs'), _n_noop('PDFs <span class="count">(%s)</span>', 'PDFs <span class="count">(%s)</span>')),		
 	);
 
 	return apply_filters('post_mime_types', $post_mime_types);