diff --git a/Dapper.MoqTests.Samples/Car.cs b/Dapper.MoqTests.Samples/Car.cs
index 959f816..5588f9d 100644
--- a/Dapper.MoqTests.Samples/Car.cs
+++ b/Dapper.MoqTests.Samples/Car.cs
@@ -1,4 +1,6 @@
-namespace Dapper.MoqTests.Samples
+using System;
+
+namespace Dapper.MoqTests.Samples
 {
     // ReSharper disable UnusedAutoPropertyAccessor.Global
     public class Car
@@ -6,5 +8,6 @@ public class Car
         public string Registration { get; set; }
         public string Make { get; set; }
         public string Model { get; set; }
+        public DateTime? DateRegistered { get; set; }
     }
 }
diff --git a/Dapper.MoqTests.Samples/Samples.cs b/Dapper.MoqTests.Samples/Samples.cs
index 6a95e67..d986ca5 100644
--- a/Dapper.MoqTests.Samples/Samples.cs
+++ b/Dapper.MoqTests.Samples/Samples.cs
@@ -197,13 +197,15 @@ public void ReturnManyComplexObjects()
             {
                 Registration = "ABC123",
                 Make = "Vauxhall",
-                Model = "Astra"
+                Model = "Astra",
+                DateRegistered = null,
             };
             var ford = new Car
             {
                 Registration = "DEF456",
                 Make = "Ford",
-                Model = "Mondeo"
+                Model = "Mondeo",
+                DateRegistered = new DateTime(2022, 2, 1, 12, 11, 10),
             };
             connectionFactory
                 .Setup(f => f.OpenConnection())
@@ -215,6 +217,7 @@ from [Cars]
 
             var result = repository.GetCars();
 
+            Assert.That(result.Select(c => c.DateRegistered), Is.EquivalentTo(new DateTime?[] { null, new DateTime(2022, 2, 1, 12, 11, 10) }));
             Assert.That(result.Select(c => c.Model), Is.EquivalentTo(new[] { "Astra", "Mondeo" }));
         }
 
diff --git a/Dapper.MoqTests/ObjectExtensions.cs b/Dapper.MoqTests/ObjectExtensions.cs
index 0c71dac..f075d3c 100644
--- a/Dapper.MoqTests/ObjectExtensions.cs
+++ b/Dapper.MoqTests/ObjectExtensions.cs
@@ -24,13 +24,24 @@ public static IDataReader GetDataReader(this object value)
 
             var properties = value.GetType()
                 .GetProperties()
-                .Where(p => IsPrimitiveType(p.PropertyType))
+                .Select(p => new { Property = p, NullablePrimitiveType = NullablePrimitiveType(p.PropertyType) })
+                .Where(p => p.NullablePrimitiveType != null || IsPrimitiveType(p.Property.PropertyType))
                 .ToArray();
             var dataTable = new DataTable();
             foreach (var property in properties)
-                dataTable.Columns.Add(property.Name, property.PropertyType);
+            {
+                if (property.NullablePrimitiveType != null)
+                {
+                    var column = new DataColumn(property.Property.Name, property.NullablePrimitiveType);
+                    column.AllowDBNull = true;
+                    dataTable.Columns.Add(column);
+                    break;
+                }
+
+                dataTable.Columns.Add(property.Property.Name, property.Property.PropertyType);
+            }
 
-            var rowValues = properties.Select(p => p.GetValue(value)).ToArray();
+            var rowValues = properties.Select(p => p.Property.GetValue(value)).ToArray();
             dataTable.Rows.Add(rowValues);
 
             return new DataTableReader(dataTable);
@@ -48,15 +59,26 @@ private static DataTable GetDataTableForArray(IEnumerable value)
 
             var properties = elementType
                 .GetProperties()
-                .Where(p => IsPrimitiveType(p.PropertyType))
+                .Select(p => new { Property = p, NullablePrimitiveType = NullablePrimitiveType(p.PropertyType) })
+                .Where(p => p.NullablePrimitiveType != null || IsPrimitiveType(p.Property.PropertyType))
                 .ToArray();
             var dataTable = new DataTable();
             foreach (var property in properties)
-                dataTable.Columns.Add(property.Name, property.PropertyType);
+            {
+                if (property.NullablePrimitiveType != null)
+                {
+                    var column = new DataColumn(property.Property.Name, property.NullablePrimitiveType);
+                    column.AllowDBNull = true;
+                    dataTable.Columns.Add(column);
+                    break;
+                }
+
+                dataTable.Columns.Add(property.Property.Name, property.Property.PropertyType);
+            }
 
             foreach (var row in value)
             {
-                var rowValues = properties.Select(p => p.GetValue(row)).ToArray();
+                var rowValues = properties.Select(p => p.Property.GetValue(row)).ToArray();
                 dataTable.Rows.Add(rowValues);
             }
 
@@ -83,5 +105,16 @@ private static bool IsPrimitiveType(Type type)
         {
             return type.IsPrimitive || PrimitiveDataTypes.Contains(type);
         }
+        private static Type NullablePrimitiveType(Type type)
+        {
+            var underlyingType = Nullable.GetUnderlyingType(type);
+
+            if (underlyingType != null && IsPrimitiveType(underlyingType))
+            {
+                return underlyingType;
+            }
+
+            return null;
+        }
     }
 }