Index: wp-admin/includes/class-wp-posts-list-table.php
===================================================================
--- wp-admin/includes/class-wp-posts-list-table.php	(revision 24034)
+++ wp-admin/includes/class-wp-posts-list-table.php	(working copy)
@@ -1025,6 +1025,24 @@
 	<?php endif; // 'post' && $can_publish && current_user_can( 'edit_others_cap' ) ?>
 
 			</div>
+
+	<?php if ( $bulk ) : // post formats bulk edit
+		$all_post_formats = get_post_format_strings();
+		unset( $all_post_formats['standard'] ); 
+		?>
+		<div class="inline-edit-group">
+			<label class="alignleft" for="post_format">
+			<span class="title"><?php _ex( 'Format', 'post format' ); ?></span>
+			<select name="post_format">
+				<option value="-1"><?php _e( '&mdash; No Change &mdash;' ); ?></option>
+				<option value="0"><?php _ex( 'Standard', 'Post format' ); ?></option>
+			<?php foreach ( $all_post_formats as $slug => $format ) : ?>
+				<option value="<?php echo esc_attr( $slug ); ?>"><?php echo esc_html( $format ); ?></option>
+			<?php endforeach; ?>
+			</select></label>
+		</div>
+	<?php endif; // $bulk ?>
+
 		</div></fieldset>
 
 	<?php
Index: wp-admin/includes/post.php
===================================================================
--- wp-admin/includes/post.php	(revision 24034)
+++ wp-admin/includes/post.php	(working copy)
@@ -314,7 +314,13 @@
 
 	$post_IDs = array_map( 'intval', (array) $post_data['post'] );
 
-	$reset = array( 'post_author', 'post_status', 'post_password', 'post_parent', 'page_template', 'comment_status', 'ping_status', 'keep_private', 'tax_input', 'post_category', 'sticky' );
+	$reset = array( 
+		'post_author', 'post_status', 'post_password', 
+		'post_parent', 'page_template', 'comment_status',
+		'ping_status', 'keep_private', 'tax_input',
+		'post_category', 'sticky', 'post_format'
+	);
+
 	foreach ( $reset as $field ) {
 		if ( isset($post_data[$field]) && ( '' == $post_data[$field] || -1 == $post_data[$field] ) )
 			unset($post_data[$field]);
@@ -359,6 +365,9 @@
 		}
 	}
 
+	if ( isset( $post_data['post_format'] ) && '0' == $post_data['post_format'] )
+		$post_data['post_format'] = false;
+
 	$updated = $skipped = $locked = array();
 	foreach ( $post_IDs as $post_ID ) {
 		$post_type_object = get_post_type_object( get_post_type( $post_ID ) );
@@ -408,6 +417,9 @@
 			else
 				unstick_post( $post_ID );
 		}
+
+		if ( isset( $post_data['post_format'] ) )
+			set_post_format( $post_ID, $post_data['post_format'] );
 	}
 
 	return array( 'updated' => $updated, 'skipped' => $skipped, 'locked' => $locked );