diff --git a/Classes/PHPExcel/Shared/String.php b/Classes/PHPExcel/Shared/String.php
index 0b5f9553..3e495e82 100644
--- a/Classes/PHPExcel/Shared/String.php
+++ b/Classes/PHPExcel/Shared/String.php
@@ -443,10 +443,10 @@ class PHPExcel_Shared_String
 			$data .= self::ConvertEncoding($value, 'UTF-16LE', 'UTF-8');
 		}
 		else {
-			$data = pack('vC', $ln, 0x08);
+			$data = pack('vC', $ln, 0x09);
 			$data .= pack('v', count($arrcRuns));
 			// characters
-			$data .= $value;
+			$data .= self::ConvertEncoding($value, 'UTF-16LE', 'UTF-8');
 			foreach ($arrcRuns as $cRun){
 				$data .= pack('v', $cRun['strlen']);
 				$data .= pack('v', $cRun['fontidx']);
diff --git a/Classes/PHPExcel/Writer/Excel5/Worksheet.php b/Classes/PHPExcel/Writer/Excel5/Worksheet.php
index 730e7398..3983f74d 100644
--- a/Classes/PHPExcel/Writer/Excel5/Worksheet.php
+++ b/Classes/PHPExcel/Writer/Excel5/Worksheet.php
@@ -424,7 +424,7 @@ class PHPExcel_Writer_Excel5_Worksheet extends PHPExcel_Writer_Excel5_BIFFwriter
 			if ($cVal instanceof PHPExcel_RichText) {
 				// $this->_writeString($row, $column, $cVal->getPlainText(), $xfIndex);
 				$arrcRun = array();
-				$str_len = strlen($cVal->getPlainText());
+				$str_len = PHPExcel_Shared_String::CountCharacters($cVal->getPlainText(), 'UTF-8');
 				$str_pos = 0;
 				$elements = $cVal->getRichTextElements();
 				foreach ($elements as $element) {
@@ -437,7 +437,7 @@ class PHPExcel_Writer_Excel5_Worksheet extends PHPExcel_Writer_Excel5_BIFFwriter
 					}
 					$arrcRun[] = array('strlen' => $str_pos, 'fontidx' => $str_fontidx);
 					// Position FROM
-					$str_pos += strlen($element->getText());
+					$str_pos += PHPExcel_Shared_String::CountCharacters($element->getText(), 'UTF-8');
 				}
 				$this->_writeRichTextString($row, $column, $cVal->getPlainText(), $xfIndex, $arrcRun);
 			} else {
diff --git a/changelog.txt b/changelog.txt
index 5ab739cb..6899e331 100644
--- a/changelog.txt
+++ b/changelog.txt
@@ -43,6 +43,7 @@ Fixed in develop branch:
 - Bugfix:   (MBaker)    Work item 18844 - cache_in_memory_gzip "eats" last worksheet line, cache_in_memory doesn't
 - Bugfix:   (Progi1984) Work item GH-22 - Sheet View in Excel5 Writer
 - Bugfix:   (amironov)  Work item GH-82 - PHPExcel_Worksheet::getCellCollection() may not return last cached cell
+- Bugfix:   (teso)      Work item 18551 - Rich Text containing UTF-8 characters creating unreadable content with Excel5 Writer
 
 
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