diff --git a/ClosedXML_Tests/ClosedXML_Tests.csproj b/ClosedXML_Tests/ClosedXML_Tests.csproj
index e89fd07..bf8a300 100644
--- a/ClosedXML_Tests/ClosedXML_Tests.csproj
+++ b/ClosedXML_Tests/ClosedXML_Tests.csproj
@@ -103,6 +103,7 @@
     <Compile Include="Excel\Ranges\InsertingRangesTests.cs" />
     <Compile Include="Excel\Rows\RowTests.cs" />
     <Compile Include="Excel\Styles\ColorTests.cs" />
+    <Compile Include="Excel\Styles\NumberFormatTests.cs" />
     <Compile Include="Excel\Styles\XLFillTests.cs" />
     <Compile Include="Excel\Tables\TablesTests.cs" />
     <Compile Include="Excel\Worksheets\XLWorksheetTests.cs" />
diff --git a/ClosedXML_Tests/Excel/Styles/NumberFormatTests.cs b/ClosedXML_Tests/Excel/Styles/NumberFormatTests.cs
new file mode 100644
index 0000000..93d9ab5
--- /dev/null
+++ b/ClosedXML_Tests/Excel/Styles/NumberFormatTests.cs
@@ -0,0 +1,37 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using NUnit.Framework;
+using ClosedXML.Excel;
+using System.Data;
+
+namespace ClosedXML_Tests.Excel
+{
+    public class NumberFormatTests
+    {
+        [Test]
+        public void PreserveCellFormat()
+        {
+            using (var wb = new XLWorkbook())
+            {
+                var ws = wb.AddWorksheet("Sheet1");
+                ws.Column(1).Style.NumberFormat.Format = "yy-MM-dd";
+
+                var table = new DataTable();
+                table.Columns.Add("Date", typeof(DateTime));
+
+                for (int i = 0; i <10; i++)
+                {
+                    table.Rows.Add(new DateTime(2017, 1, 1).AddMonths(i));
+                }
+
+                ws.Cell("B1").Value = table.Columns[0].DataType;
+
+                ws.Cell("A1").InsertData(table.AsEnumerable());
+
+                Assert.AreEqual("yy-MM-dd", ws.Cell("A5").Style.DateFormat.Format);
+            }
+        }
+    }
+}