--- a/src/ooxml/java/org/apache/poi/xssf/usermodel/XSSFWorkbook.java	
+++ a/src/ooxml/java/org/apache/poi/xssf/usermodel/XSSFWorkbook.java	
@@ -37,6 +37,7 @@ 
 import java.util.Locale;
 import java.util.Map;
 import java.util.NoSuchElementException;
+import java.util.Objects;
 import java.util.regex.Pattern;
 
 import javax.xml.namespace.QName;
@@ -90,6 +91,7 @@ 
 import org.apache.poi.xssf.model.SharedStringsTable;
 import org.apache.poi.xssf.model.StylesTable;
 import org.apache.poi.xssf.model.ThemesTable;
+import org.apache.poi.xssf.usermodel.extensions.XSSFCellBorder.BorderSide;
 import org.apache.poi.xssf.usermodel.helpers.XSSFFormulaUtils;
 import org.apache.xmlbeans.XmlException;
 import org.apache.xmlbeans.XmlObject;
@@ -659,6 +661,79 @@ 
         }
         return clonedSheet;
     }
+    
+    /**
+     * Copies a CellStyle from another Workbook to the current one. If the new CellStyle already exists (same font, fill, ...)
+     * then the already existing one will be returned, otherwise a new one is created.
+     * 
+     * See {@link #cloneCellStyle(XSSFCellStyle, boolean)} if you want to simply add the new Style without any searching.
+     *
+     * @param src The CellStyle that is going to be cloned
+     * @return CellStyle The created or looked up CellStyle in the current Workbook
+     */
+    public XSSFCellStyle cloneCellStyle(XSSFCellStyle src) {
+        return cloneCellStyle(src, true);
+    }
+    
+    /**
+     * Copies a CellStyle from another Workbook to the current one. If the new CellStyle already exists (same font, fill, ...)
+     * - and clean is set to true - then the already existing one will be returned, otherwise a new one is created, added to the workbook and then returned.
+     *
+     * @param src The CellStyle that is going to be cloned
+     * @param clean If set to true, this method attempts to find a already existing CellStyle which has the same properties first
+     * @return CellStyle The created or looked up CellStyle in the current Workbook
+     */
+    public XSSFCellStyle cloneCellStyle(XSSFCellStyle src, boolean clean) {
+        
+        XSSFCellStyle returnStyle = null;
+        
+        // Search for an existing Style that fits the source
+        // Caution: Even if the Style is the same, the underlying borders, fills, ... may differ!
+        if(clean){
+            for(int i = 0; i < this.getNumCellStyles(); i++){
+                XSSFCellStyle currCellStyle = this.getCellStyleAt(i);
+                
+                // TODO: Order from "most probably not the same" to "most probably the same" to increase performance
+                //       e.g.: It is more likely that the Font changed than WrapText
+                // TODO: Let the CellStyle decide if it equals another one (CellStyle.deepEquals()?!)
+                if(Objects.equals(currCellStyle.getHidden(), src.getHidden())
+                        && Objects.equals(currCellStyle.getAlignmentEnum(), src.getAlignmentEnum())
+                        && Objects.equals(currCellStyle.getBorderBottomEnum(), src.getBorderBottomEnum())
+                        && Objects.equals(currCellStyle.getRotation(), src.getRotation())
+                        && Objects.equals(currCellStyle.getFillPatternEnum(), src.getFillPatternEnum())
+                        && Objects.equals(currCellStyle.getFillBackgroundXSSFColor(), src.getFillBackgroundXSSFColor())
+                        && Objects.equals(currCellStyle.getFillForegroundXSSFColor(), src.getFillForegroundXSSFColor())
+                        && Objects.equals(currCellStyle.getFont(), src.getFont())
+                        && Objects.equals(currCellStyle.getBorderTopEnum(), src.getBorderTopEnum())
+                        && Objects.equals(currCellStyle.getTopBorderXSSFColor(), src.getTopBorderXSSFColor())
+                        && Objects.equals(currCellStyle.getBorderRightEnum(), src.getBorderRightEnum())
+                        && Objects.equals(currCellStyle.getRightBorderXSSFColor(), src.getRightBorderXSSFColor())
+                        && Objects.equals(currCellStyle.getBorderBottomEnum(), src.getBorderBottomEnum())
+                        && Objects.equals(currCellStyle.getBottomBorderXSSFColor(), src.getBottomBorderXSSFColor())
+                        && Objects.equals(currCellStyle.getBorderLeftEnum(), src.getBorderLeftEnum())
+                        && Objects.equals(currCellStyle.getLeftBorderXSSFColor(), src.getLeftBorderXSSFColor())
+                        && Objects.equals(currCellStyle.getDataFormat(), src.getDataFormat())
+                        && Objects.equals(currCellStyle.getIndention(), src.getIndention())
+                        && Objects.equals(currCellStyle.getLocked(), src.getLocked())
+                        && Objects.equals(currCellStyle.getQuotePrefixed(), src.getQuotePrefixed())
+                        && Objects.equals(currCellStyle.getShrinkToFit(), src.getShrinkToFit())
+                        && Objects.equals(currCellStyle.getVerticalAlignmentEnum(), src.getVerticalAlignmentEnum())
+                        && Objects.equals(currCellStyle.getWrapText(), src.getWrapText())
+                        ){
+                    returnStyle = currCellStyle;
+                }
+            }
+        }
+            
+        if(returnStyle == null){
+            // If none exists: Create one (use XSSFCellStyles cloneStyle)
+            returnStyle = this.createCellStyle();
+            returnStyle.cloneStyleFrom(src);
+        }
+
+        return returnStyle;
+    }
+    
     
     /**
      * @since 3.14-Beta1
@@ -2470,4 +2545,6 @@ 
 
         return oleId;
     }
+
+
 }