diff --git a/src/xlsx/xlsxworkbook.cpp b/src/xlsx/xlsxworkbook.cpp
index b86e447..fafc931 100755
--- a/src/xlsx/xlsxworkbook.cpp
+++ b/src/xlsx/xlsxworkbook.cpp
@@ -55,6 +55,9 @@ WorkbookPrivate::WorkbookPrivate(Workbook *q) :
     activesheet = 0;
     firstsheet = 0;
     table_count = 0;
+
+    last_sheet_index = 0;
+    last_sheet_id = 0;
 }
 
 Workbook::Workbook() :
@@ -135,10 +138,9 @@ Worksheet *Workbook::addWorksheet(const QString &name)
 Worksheet *Workbook::insertWorkSheet(int index, const QString &name)
 {
     Q_D(Workbook);
-    static int lastIndex = -1;
     QString worksheetName = name;
     if (!name.isEmpty()) {
-        //If user given an already in-use name, we should not continue any more!
+        //If user given an already in-used name, we should not continue any more!
         for (int i=0; i<d->worksheets.size(); ++i) {
             if (d->worksheets[i]->sheetName() == name) {
                 return 0;
@@ -147,9 +149,9 @@ Worksheet *Workbook::insertWorkSheet(int index, const QString &name)
     } else {
         bool exists;
         do {
-            ++lastIndex;
+            ++d->last_sheet_index;
             exists = false;
-            worksheetName = QStringLiteral("Sheet%1").arg(lastIndex+1);
+            worksheetName = QStringLiteral("Sheet%1").arg(d->last_sheet_index);
             for (int i=0; i<d->worksheets.size(); ++i) {
                 if (d->worksheets[i]->sheetName() == worksheetName)
                     exists = true;
@@ -157,7 +159,8 @@ Worksheet *Workbook::insertWorkSheet(int index, const QString &name)
         } while (exists);
     }
 
-    Worksheet *sheet = new Worksheet(worksheetName, this);
+    ++d->last_sheet_id;
+    Worksheet *sheet = new Worksheet(worksheetName, d->last_sheet_id, this);
     d->worksheets.insert(index, QSharedPointer<Worksheet>(sheet));
     d->activesheet = index;
     return sheet;
@@ -284,7 +287,7 @@ void Workbook::saveToXmlFile(QIODevice *device)
         QSharedPointer<Worksheet> sheet = d->worksheets[i];
         writer.writeEmptyElement(QStringLiteral("sheet"));
         writer.writeAttribute(QStringLiteral("name"), sheet->sheetName());
-        writer.writeAttribute(QStringLiteral("sheetId"), QString::number(i+1));
+        writer.writeAttribute(QStringLiteral("sheetId"), QString::number(sheet->sheetId()));
         if (sheet->isHidden())
             writer.writeAttribute(QStringLiteral("state"), QStringLiteral("hidden"));
         writer.writeAttribute(QStringLiteral("r:id"), QStringLiteral("rId%1").arg(i+1));
diff --git a/src/xlsx/xlsxworkbook_p.h b/src/xlsx/xlsxworkbook_p.h
index 719bd48..7eb01b6 100644
--- a/src/xlsx/xlsxworkbook_p.h
+++ b/src/xlsx/xlsxworkbook_p.h
@@ -58,6 +58,10 @@ public:
     int activesheet;
     int firstsheet;
     int table_count;
+
+    //Used to generate new sheet name and id
+    int last_sheet_index;
+    int last_sheet_id;
 };
 
 }
diff --git a/src/xlsx/xlsxworksheet.cpp b/src/xlsx/xlsxworksheet.cpp
index 734705a..5733287 100755
--- a/src/xlsx/xlsxworksheet.cpp
+++ b/src/xlsx/xlsxworksheet.cpp
@@ -195,13 +195,15 @@ int WorksheetPrivate::checkDimensions(int row, int col, bool ignore_row, bool ig
 /*!
  * \brief Worksheet::Worksheet
  * \param name Name of the worksheet
- * \param index Index of the worksheet in the workbook
- * \param parent
+ * \param id : An integer representing the internal id of the
+ *             sheet which is used by .xlsx revision part.
+ *             (Note: id is not the index of the sheet in workbook)
  */
-Worksheet::Worksheet(const QString &name, Workbook *workbook) :
+Worksheet::Worksheet(const QString &name, int id, Workbook *workbook) :
     d_ptr(new WorksheetPrivate(this))
 {
     d_ptr->name = name;
+    d_ptr->id = id;
     if (!workbook) //For unit test propose only. Ignore the memery leak.
         workbook = new Workbook;
     d_ptr->workbook = workbook;
@@ -253,6 +255,12 @@ void Worksheet::setSelected(bool select)
     d->selected = select;
 }
 
+int Worksheet::sheetId() const
+{
+    Q_D(const Worksheet);
+    return d->id;
+}
+
 void Worksheet::setRightToLeft(bool enable)
 {
     Q_D(Worksheet);
diff --git a/src/xlsx/xlsxworksheet.h b/src/xlsx/xlsxworksheet.h
index 353e0b3..320e6bd 100755
--- a/src/xlsx/xlsxworksheet.h
+++ b/src/xlsx/xlsxworksheet.h
@@ -85,7 +85,7 @@ private:
     friend class Package;
     friend class Workbook;
     friend class ::WorksheetTest;
-    Worksheet(const QString &sheetName, Workbook *book);
+    Worksheet(const QString &sheetName, int sheetId, Workbook *book);
 
     void saveToXmlFile(QIODevice *device);
     QByteArray saveToXmlData();
@@ -97,6 +97,7 @@ private:
     bool isSelected() const;
     void setHidden(bool hidden);
     void setSelected(bool select);
+    int sheetId() const;
     QStringList externUrlList() const;
     QStringList externDrawingList() const;
     QList<QPair<QString, QString> > drawingLinks() const;
diff --git a/src/xlsx/xlsxworksheet_p.h b/src/xlsx/xlsxworksheet_p.h
index 1c0163e..1b1f395 100644
--- a/src/xlsx/xlsxworksheet_p.h
+++ b/src/xlsx/xlsxworksheet_p.h
@@ -223,6 +223,7 @@ public:
     bool default_row_zeroed;
 
     QString name;
+    int id;
     bool hidden;
     bool selected;
     bool right_to_left;
diff --git a/tests/auto/worksheet/tst_worksheet.cpp b/tests/auto/worksheet/tst_worksheet.cpp
index f70da1f..93afb49 100644
--- a/tests/auto/worksheet/tst_worksheet.cpp
+++ b/tests/auto/worksheet/tst_worksheet.cpp
@@ -34,7 +34,7 @@ WorksheetTest::WorksheetTest()
 
 void WorksheetTest::testEmptySheet()
 {
-    QXlsx::Worksheet sheet("", 0);
+    QXlsx::Worksheet sheet("", 1, 0);
     sheet.write("B1", 123);
     QByteArray xmldata = sheet.saveToXmlData();
 
@@ -43,7 +43,7 @@ void WorksheetTest::testEmptySheet()
 
 void WorksheetTest::testWriteCells()
 {
-    QXlsx::Worksheet sheet("", 0);
+    QXlsx::Worksheet sheet("", 1, 0);
     sheet.write("A1", 123);
     sheet.write("A2", "Hello");
     sheet.writeInlineString(2, 0, "Hello inline"); //A3
@@ -65,7 +65,7 @@ void WorksheetTest::testWriteCells()
 
 void WorksheetTest::testWriteHyperlinks()
 {
-    QXlsx::Worksheet sheet("", 0);
+    QXlsx::Worksheet sheet("", 1, 0);
     sheet.write("A1", QUrl::fromUserInput("http://qt-project.org"));
     sheet.write("B1", QUrl::fromUserInput("http://qt-project.org/abc"));
     sheet.write("C1", QUrl::fromUserInput("http://qt-project.org/abc.html#test"));
@@ -89,7 +89,7 @@ void WorksheetTest::testWriteHyperlinks()
 
 void WorksheetTest::testMerge()
 {
-    QXlsx::Worksheet sheet("", 0);
+    QXlsx::Worksheet sheet("", 1, 0);
     sheet.write("B1", 123);
     sheet.mergeCells("B1:B5");
     QByteArray xmldata = sheet.saveToXmlData();
@@ -99,7 +99,7 @@ void WorksheetTest::testMerge()
 
 void WorksheetTest::testUnMerge()
 {
-    QXlsx::Worksheet sheet("", 0);
+    QXlsx::Worksheet sheet("", 1, 0);
     sheet.write("B1", 123);
     sheet.mergeCells("B1:B5");
     sheet.unmergeCells("B1:B5");
@@ -125,7 +125,7 @@ void WorksheetTest::testReadSheetData()
     QXlsx::XmlStreamReader reader(xmlData);
     reader.readNextStartElement();//current node is sheetData
 
-    QXlsx::Worksheet sheet("", 0);
+    QXlsx::Worksheet sheet("", 1, 0);
     sheet.d_ptr->sharedStrings()->addSharedString("Hello");
     sheet.d_ptr->readSheetData(reader);
 
@@ -162,7 +162,7 @@ void WorksheetTest::testReadColsInfo()
     QXlsx::XmlStreamReader reader(xmlData);
     reader.readNextStartElement();//current node is cols
 
-    QXlsx::Worksheet sheet("", 0);
+    QXlsx::Worksheet sheet("", 1, 0);
     sheet.d_ptr->readColumnsInfo(reader);
 
     QCOMPARE(sheet.d_ptr->colsInfo.size(), 1);
@@ -182,7 +182,7 @@ void WorksheetTest::testReadRowsInfo()
     QXlsx::XmlStreamReader reader(xmlData);
     reader.readNextStartElement();//current node is sheetData
 
-    QXlsx::Worksheet sheet("", 0);
+    QXlsx::Worksheet sheet("", 1, 0);
     sheet.d_ptr->readSheetData(reader);
 
     QCOMPARE(sheet.d_ptr->rowsInfo.size(), 1);
@@ -196,7 +196,7 @@ void WorksheetTest::testReadMergeCells()
     QXlsx::XmlStreamReader reader(xmlData);
     reader.readNextStartElement();//current node is mergeCells
 
-    QXlsx::Worksheet sheet("", 0);
+    QXlsx::Worksheet sheet("", 1, 0);
     sheet.d_ptr->readMergeCells(reader);
 
     QCOMPARE(sheet.d_ptr->merges.size(), 2);