diff --git a/ooxml/XSSF/UserModel/XSSFCellStyle.cs b/ooxml/XSSF/UserModel/XSSFCellStyle.cs
index a51d634e4..e393f89ae 100644
--- a/ooxml/XSSF/UserModel/XSSFCellStyle.cs
+++ b/ooxml/XSSF/UserModel/XSSFCellStyle.cs
@@ -695,7 +695,11 @@ public bool IsHidden
         {
             get
             {
-                return _cellXf.IsSetProtection() && _cellXf.protection.IsSetHidden() && _cellXf.protection.hidden;
+                if (!_cellXf.IsSetProtection() || !_cellXf.protection.IsSetHidden())
+                {
+                    return false;
+                }
+                return _cellXf.protection.hidden;
             }
             set
             {
@@ -804,7 +808,7 @@ public bool IsLocked
             {
                 if (!_cellXf.IsSetProtection())
                 {
-                    return false;
+                    return true;
                 }
                 return _cellXf.protection.locked;
             }
diff --git a/testcases/ooxml/XSSF/UserModel/TestXSSFCellStyle.cs b/testcases/ooxml/XSSF/UserModel/TestXSSFCellStyle.cs
index 8de136aa9..f140e5d4a 100644
--- a/testcases/ooxml/XSSF/UserModel/TestXSSFCellStyle.cs
+++ b/testcases/ooxml/XSSF/UserModel/TestXSSFCellStyle.cs
@@ -718,7 +718,7 @@ public void TestGetSetHidden()
         [Test]
         public void TestGetSetLocked()
         {
-            Assert.IsFalse(cellStyle.IsLocked);
+            Assert.IsTrue(cellStyle.IsLocked);
             cellStyle.IsLocked = (true);
             Assert.IsTrue(cellStyle.IsLocked);
             cellStyle.IsLocked = (false);