diff --git a/src/Spout/Reader/XLSX/Helper/SharedStringsHelper.php b/src/Spout/Reader/XLSX/Helper/SharedStringsHelper.php
index 750c53e..350024a 100644
--- a/src/Spout/Reader/XLSX/Helper/SharedStringsHelper.php
+++ b/src/Spout/Reader/XLSX/Helper/SharedStringsHelper.php
@@ -159,7 +159,15 @@ class SharedStringsHelper
             $xmlReader->read();
         }
 
-        return intval($xmlReader->getAttribute('uniqueCount'));
+        $uniqueCount = $xmlReader->getAttribute('uniqueCount');
+
+        // some software do not add the "uniqueCount" attribute but only use the "count" one
+        // @see https://github.com/box/spout/issues/254
+        if ($uniqueCount === null) {
+            $uniqueCount = $xmlReader->getAttribute('count');
+        }
+
+        return intval($uniqueCount);
     }
 
     /**
diff --git a/tests/Spout/Reader/XLSX/ReaderTest.php b/tests/Spout/Reader/XLSX/ReaderTest.php
index 2703799..c705f2f 100644
--- a/tests/Spout/Reader/XLSX/ReaderTest.php
+++ b/tests/Spout/Reader/XLSX/ReaderTest.php
@@ -112,6 +112,20 @@ class ReaderTest extends \PHPUnit_Framework_TestCase
         $this->assertEquals($expectedRows, $allRows);
     }
 
+    /**
+     * @return void
+     */
+    public function testReadShouldSupportSheetWithSharedStringsMissingUniqueCountAttribute()
+    {
+        $allRows = $this->getAllRowsForFile('one_sheet_with_shared_strings_missing_unique_count.xlsx');
+
+        $expectedRows = [
+            ['s1--A1', 's1--B1'],
+            ['s1--A2', 's1--B2'],
+        ];
+        $this->assertEquals($expectedRows, $allRows);
+    }
+
     /**
      * @return void
      */
diff --git a/tests/resources/xlsx/one_sheet_with_shared_strings_missing_unique_count.xlsx b/tests/resources/xlsx/one_sheet_with_shared_strings_missing_unique_count.xlsx
new file mode 100644
index 0000000..8001e4b
Binary files /dev/null and b/tests/resources/xlsx/one_sheet_with_shared_strings_missing_unique_count.xlsx differ