diff --git a/wp-includes/category-template.php b/wp-includes/category-template.php
index 452930bcd5..66b31cec5f 100644
--- a/wp-includes/category-template.php
+++ b/wp-includes/category-template.php
@@ -40,7 +40,7 @@ function get_category_parents( $id, $link = false, $separator = '/', $nicename =
 	if ( $nicename )
 		$name = $parent->slug;
 	else
-		$name = $parent->cat_name;
+		$name = $parent->name;
 
 	if ( $parent->parent && ( $parent->parent != $parent->term_id ) && !in_array( $parent->parent, $visited ) ) {
 		$visited[] = $parent->parent;
@@ -48,7 +48,7 @@ function get_category_parents( $id, $link = false, $separator = '/', $nicename =
 	}
 
 	if ( $link )
-		$chain .= '<a href="' . get_category_link( $parent->term_id ) . '" title="' . esc_attr( sprintf( __( "View all posts in %s" ), $parent->cat_name ) ) . '">'.$name.'</a>' . $separator;
+		$chain .= '<a href="' . get_category_link( $parent->term_id ) . '" title="' . esc_attr( sprintf( __( "View all posts in %s" ), $parent->name ) ) . '">'.$name.'</a>' . $separator;
 	else
 		$chain .= $name.$separator;
 	return $chain;
@@ -183,7 +183,7 @@ function get_the_category_list( $separator = '', $parents='', $post_id = false )
 					break;
 				case '':
 				default:
-					$thelist .= '<a href="' . get_category_link( $category->term_id ) . '" title="' . esc_attr( sprintf( __( "View all posts in %s" ), $category->name ) ) . '" ' . $rel . '>' . $category->cat_name.'</a></li>';
+					$thelist .= '<a href="' . get_category_link( $category->term_id ) . '" title="' . esc_attr( sprintf( __( "View all posts in %s" ), $category->name ) ) . '" ' . $rel . '>' . $category->name.'</a></li>';
 			}
 		}
 		$thelist .= '</ul>';
@@ -196,13 +196,13 @@ function get_the_category_list( $separator = '', $parents='', $post_id = false )
 				case 'multiple':
 					if ( $category->parent )
 						$thelist .= get_category_parents( $category->parent, true, $separator );
-					$thelist .= '<a href="' . get_category_link( $category->term_id ) . '" title="' . esc_attr( sprintf( __( "View all posts in %s" ), $category->name ) ) . '" ' . $rel . '>' . $category->cat_name.'</a>';
+					$thelist .= '<a href="' . get_category_link( $category->term_id ) . '" title="' . esc_attr( sprintf( __( "View all posts in %s" ), $category->name ) ) . '" ' . $rel . '>' . $category->name.'</a>';
 					break;
 				case 'single':
 					$thelist .= '<a href="' . get_category_link( $category->term_id ) . '" title="' . esc_attr( sprintf( __( "View all posts in %s" ), $category->name ) ) . '" ' . $rel . '>';
 					if ( $category->parent )
 						$thelist .= get_category_parents( $category->parent, false, $separator );
-					$thelist .= "$category->cat_name</a>";
+					$thelist .= "$category->name</a>";
 					break;
 				case '':
 				default:
diff --git a/wp-includes/class-wp-xmlrpc-server.php b/wp-includes/class-wp-xmlrpc-server.php
index fce1131dc5..d9b67734bf 100644
--- a/wp-includes/class-wp-xmlrpc-server.php
+++ b/wp-includes/class-wp-xmlrpc-server.php
@@ -946,8 +946,8 @@ class wp_xmlrpc_server extends IXR_Server {
 		$args = array('get' => 'all', 'number' => $max_results, 'name__like' => $category);
 		foreach ( (array) get_categories($args) as $cat ) {
 			$category_suggestions[] = array(
-				"category_id"	=> $cat->cat_ID,
-				"category_name"	=> $cat->cat_name
+				"category_id"	=> $cat->term_id,
+				"category_name"	=> $cat->name
 			);
 		}
 
@@ -3409,4 +3409,4 @@ class wp_xmlrpc_server extends IXR_Server {
 		return $pingbacks;
 	}
 }
-?>
\ No newline at end of file
+?>
diff --git a/wp-includes/post-template.php b/wp-includes/post-template.php
index b14cb3a4db..0b1db1a1bf 100644
--- a/wp-includes/post-template.php
+++ b/wp-includes/post-template.php
@@ -352,7 +352,7 @@ function get_post_class( $class = '', $post_id = null ) {
 		foreach ( (array) get_the_category($post->ID) as $cat ) {
 			if ( empty($cat->slug ) )
 				continue;
-			$classes[] = 'category-' . sanitize_html_class($cat->slug, $cat->cat_ID);
+			$classes[] = 'category-' . sanitize_html_class($cat->slug, $cat->term_id);
 		}
 	}