diff --git a/wp-admin/import/blogger.php b/wp-admin/import/blogger.php
index fef2fe8e37..0879cd11b0 100644
--- a/wp-admin/import/blogger.php
+++ b/wp-admin/import/blogger.php
@@ -550,7 +550,7 @@ class Blogger_Import {
 		$post_status  = isset( $entry->draft ) ? 'draft' : 'publish';
 
 		// Clean up content
-		$post_content = preg_replace('|<(/?[A-Z]+)|e', "'<' . strtolower('$1')", $post_content);
+		$post_content = preg_replace_callback('|<(/?[A-Z]+)|', create_function('$match', 'return "<" . strtolower($match[1]);'), $post_content);
 		$post_content = str_replace('<br>', '<br />', $post_content);
 		$post_content = str_replace('<hr>', '<hr />', $post_content);
 
@@ -603,7 +603,7 @@ class Blogger_Import {
 		$comment_content = addslashes( $this->no_apos( html_entity_decode( $entry->content ) ) );
 
 		// Clean up content
-		$comment_content = preg_replace('|<(/?[A-Z]+)|e', "'<' . strtolower('$1')", $comment_content);
+		$comment_content = preg_replace_callback('|<(/?[A-Z]+)|', create_function('$match', 'return "<" . strtolower($match[1]);'), $comment_content);
 		$comment_content = str_replace('<br>', '<br />', $comment_content);
 		$comment_content = str_replace('<hr>', '<hr />', $comment_content);
 
diff --git a/wp-admin/import/blogware.php b/wp-admin/import/blogware.php
index 1adcc1d5d3..afec323c3b 100644
--- a/wp-admin/import/blogware.php
+++ b/wp-admin/import/blogware.php
@@ -89,7 +89,7 @@ class BW_Import {
 			}
 
 			// Clean up content
-			$post_content = preg_replace('|<(/?[A-Z]+)|e', "'<' . strtolower('$1')", $post_content);
+			$post_content = preg_replace_callback('|<(/?[A-Z]+)|', create_function('$match', 'return "<" . strtolower($match[1]);'), $post_content);
 			$post_content = str_replace('<br>', '<br />', $post_content);
 			$post_content = str_replace('<hr>', '<hr />', $post_content);
 			$post_content = $wpdb->escape($post_content);
@@ -129,7 +129,7 @@ class BW_Import {
 					$comment_content = $this->unhtmlentities($comment_content);
 
 					// Clean up content
-					$comment_content = preg_replace('|<(/?[A-Z]+)|e', "'<' . strtolower('$1')", $comment_content);
+					$comment_content = preg_replace_callback('|<(/?[A-Z]+)|', create_function('$match', 'return "<" . strtolower($match[1]);'), $comment_content);
 					$comment_content = str_replace('<br>', '<br />', $comment_content);
 					$comment_content = str_replace('<hr>', '<hr />', $comment_content);
 					$comment_content = $wpdb->escape($comment_content);
diff --git a/wp-admin/import/livejournal.php b/wp-admin/import/livejournal.php
index d51b798cd8..e1161df439 100644
--- a/wp-admin/import/livejournal.php
+++ b/wp-admin/import/livejournal.php
@@ -71,7 +71,7 @@ class LJ_Import {
 			$post_content = $this->unhtmlentities($post_content);
 
 			// Clean up content
-			$post_content = preg_replace('|<(/?[A-Z]+)|e', "'<' . strtolower('$1')", $post_content);
+			$post_content = preg_replace_callback('|<(/?[A-Z]+)|', create_function('$match', 'return "<" . strtolower($match[1]);'), $post_content);
 			$post_content = str_replace('<br>', '<br />', $post_content);
 			$post_content = str_replace('<hr>', '<hr />', $post_content);
 			$post_content = $wpdb->escape($post_content);
@@ -107,7 +107,7 @@ class LJ_Import {
 					$comment_content = $this->unhtmlentities($comment_content);
 
 					// Clean up content
-					$comment_content = preg_replace('|<(/?[A-Z]+)|e', "'<' . strtolower('$1')", $comment_content);
+					$comment_content = preg_replace_callback('|<(/?[A-Z]+)|', create_function('$match', 'return "<" . strtolower($match[1]);'), $comment_content);
 					$comment_content = str_replace('<br>', '<br />', $comment_content);
 					$comment_content = str_replace('<hr>', '<hr />', $comment_content);
 					$comment_content = $wpdb->escape($comment_content);
diff --git a/wp-admin/import/rss.php b/wp-admin/import/rss.php
index d672b064c9..832396f50e 100644
--- a/wp-admin/import/rss.php
+++ b/wp-admin/import/rss.php
@@ -103,7 +103,7 @@ class RSS_Import {
 			}
 
 			// Clean up content
-			$post_content = preg_replace('|<(/?[A-Z]+)|e', "'<' . strtolower('$1')", $post_content);
+			$post_content = preg_replace_callback('|<(/?[A-Z]+)|', create_function('$match', 'return "<" . strtolower($match[1]);'), $post_content);
 			$post_content = str_replace('<br>', '<br />', $post_content);
 			$post_content = str_replace('<hr>', '<hr />', $post_content);
 
diff --git a/wp-admin/import/wordpress.php b/wp-admin/import/wordpress.php
index 86b7a07874..762ccb3f2c 100644
--- a/wp-admin/import/wordpress.php
+++ b/wp-admin/import/wordpress.php
@@ -381,12 +381,12 @@ class WP_Import {
 		$post_author    = $this->get_tag( $post, 'dc:creator' );
 
 		$post_excerpt = $this->get_tag( $post, 'excerpt:encoded' );
-		$post_excerpt = preg_replace('|<(/?[A-Z]+)|e', "'<' . strtolower('$1')", $post_excerpt);
+		$post_excerpt = preg_replace_callback('|<(/?[A-Z]+)|', create_function('$match', 'return "<" . strtolower($match[1]);'), $post_excerpt);
 		$post_excerpt = str_replace('<br>', '<br />', $post_excerpt);
 		$post_excerpt = str_replace('<hr>', '<hr />', $post_excerpt);
 
 		$post_content = $this->get_tag( $post, 'content:encoded' );
-		$post_content = preg_replace('|<(/?[A-Z]+)|e', "'<' . strtolower('$1')", $post_content);
+		$post_content = preg_replace_callback('|<(/?[A-Z]+)|', create_function('$match', 'return "<" . strtolower($match[1]);'), $post_content);
 		$post_content = str_replace('<br>', '<br />', $post_content);
 		$post_content = str_replace('<hr>', '<hr />', $post_content);
 
diff --git a/wp-includes/formatting.php b/wp-includes/formatting.php
index 4cc02b27ff..90729796de 100644
--- a/wp-includes/formatting.php
+++ b/wp-includes/formatting.php
@@ -1317,8 +1317,7 @@ function wp_iso_descrambler($string) {
 		return $string;
 	} else {
 		$subject = str_replace('_', ' ', $matches[2]);
-		/** @todo use preg_replace_callback() */
-		$subject = preg_replace('#\=([0-9a-f]{2})#ei', "chr(hexdec(strtolower('$1')))", $subject);
+		$subject = preg_replace_callback('#\=([0-9a-f]{2})#i', create_function('$match', 'return chr(hexdec(strtolower($match[1])));'), $subject);
 		return $subject;
 	}
 }
diff --git a/wp-includes/kses.php b/wp-includes/kses.php
index c333d4c319..634cd4931e 100644
--- a/wp-includes/kses.php
+++ b/wp-includes/kses.php
@@ -394,8 +394,11 @@ function wp_kses_version() {
  * @return string Content with fixed HTML tags
  */
 function wp_kses_split($string, $allowed_html, $allowed_protocols) {
-	return preg_replace('%((<!--.*?(-->|$))|(<[^>]*(>|$)|>))%e',
-	"wp_kses_split2('\\1', \$allowed_html, ".'$allowed_protocols)', $string);
+	global $pass_allowed_html, $pass_allowed_protocols;
+	$pass_allowed_html = $allowed_html;
+	$pass_allowed_protocols = $allowed_protocols;
+	return preg_replace_callback('%((<!--.*?(-->|$))|(<[^>]*(>|$)|>))%',
+		create_function('$match', 'global $pass_allowed_html, $pass_allowed_protocols; return wp_kses_split2($match[1], $pass_allowed_html, $pass_allowed_protocols);'), $string);
 }
 
 /**
@@ -999,8 +1002,8 @@ function valid_unicode($i) {
  * @return string Content after decoded entities
  */
 function wp_kses_decode_entities($string) {
-	$string = preg_replace('/&#([0-9]+);/e', 'chr("\\1")', $string);
-	$string = preg_replace('/&#[Xx]([0-9A-Fa-f]+);/e', 'chr(hexdec("\\1"))', $string);
+	$string = preg_replace_callback('/&#([0-9]+);/', create_function('$match', 'return chr($match[1]);'), $string);
+	$string = preg_replace_callback('/&#[Xx]([0-9A-Fa-f]+);/', create_function('$match', 'return chr(hexdec($match[1]));'), $string);
 
 	return $string;
 }
diff --git a/wp-includes/post-template.php b/wp-includes/post-template.php
index 0da75e7833..8db1f196b0 100644
--- a/wp-includes/post-template.php
+++ b/wp-includes/post-template.php
@@ -223,7 +223,7 @@ function get_the_content($more_link_text = null, $stripteaser = 0, $more_file =
 
 	}
 	if ( $preview ) // preview fix for javascript bug with foreign languages
-		$output =	preg_replace('/\%u([0-9A-F]{4,4})/e',	"'&#'.base_convert('\\1',16,10).';'", $output);
+		$output =	preg_replace_callback('/\%u([0-9A-F]{4})/', create_function('$match', 'return "&#" . base_convert($match[1], 16, 10) . ";";'), $output);
 
 	return $output;
 }