diff --git a/src/Microsoft.OpenApi/Writers/OpenApiWriterBase.cs b/src/Microsoft.OpenApi/Writers/OpenApiWriterBase.cs
index 63096135b..172e3fa2a 100644
--- a/src/Microsoft.OpenApi/Writers/OpenApiWriterBase.cs
+++ b/src/Microsoft.OpenApi/Writers/OpenApiWriterBase.cs
@@ -157,13 +157,21 @@ public virtual void WriteValue(long value)
         }
 
         /// <summary>
-        /// Write dateTimeOffset value.
+        /// Write DateTime value.
         /// </summary>
-        /// <param name="value">The decimal value.</param>
+        /// <param name="value">The DateTime value.</param>
+        public virtual void WriteValue(DateTime value)
+        {
+            this.WriteValue(value.ToString("o"));
+        }
+
+        /// <summary>
+        /// Write DateTimeOffset value.
+        /// </summary>
+        /// <param name="value">The DateTimeOffset value.</param>
         public virtual void WriteValue(DateTimeOffset value)
         {
-            WriteValueSeparator();
-            Writer.Write(value.ToString("o"));
+            this.WriteValue(value.ToString("o"));
         }
 
         /// <summary>
@@ -218,6 +226,10 @@ public virtual void WriteValue(object value)
             {
                 WriteValue((decimal)value);
             }
+            else if ( type == typeof(DateTime) || type == typeof(DateTime?) )
+            {
+                WriteValue((DateTime)value);
+            }
             else if (type == typeof(DateTimeOffset) || type == typeof(DateTimeOffset?))
             {
                 WriteValue((DateTimeOffset)value);
diff --git a/test/Microsoft.OpenApi.Tests/Writers/OpenApiJsonWriterTests.cs b/test/Microsoft.OpenApi.Tests/Writers/OpenApiJsonWriterTests.cs
index e4a90c280..253e74c06 100644
--- a/test/Microsoft.OpenApi.Tests/Writers/OpenApiJsonWriterTests.cs
+++ b/test/Microsoft.OpenApi.Tests/Writers/OpenApiJsonWriterTests.cs
@@ -1,6 +1,7 @@
 // Copyright (c) Microsoft Corporation. All rights reserved.
 // Licensed under the MIT license. 
 
+using System;
 using System.Collections;
 using System.Collections.Generic;
 using System.IO;
@@ -134,6 +135,17 @@ public static IEnumerable<object[]> WriteMapAsJsonShouldMatchExpectedTestCasesCo
                 }
             };
 
+            // DateTime
+            yield return new object[]
+            {
+                new Dictionary<string, object>
+                {
+                    ["property1"] = new DateTime(1970, 01, 01),
+                    ["property2"] = new DateTimeOffset(new DateTime(1970, 01, 01)),
+                    ["property3"] = new DateTime(2018, 04, 03),
+                }
+            };
+
             // Nested map
             yield return new object[]
             {
@@ -183,7 +195,12 @@ public static IEnumerable<object[]> WriteMapAsJsonShouldMatchExpectedTestCasesCo
 
         private void WriteValueRecursive(OpenApiJsonWriter writer, object value)
         {
-            if (value == null || value.GetType().IsPrimitive || value is decimal || value is string)
+            if (value == null 
+                || value.GetType().IsPrimitive 
+                || value is decimal 
+                || value is string 
+                || value is DateTimeOffset
+                || value is DateTime)
             {
                 writer.WriteValue(value);
             }
@@ -230,5 +247,49 @@ public void WriteMapAsJsonShouldMatchExpected(IDictionary<string, object> inputM
             // Assert
             parsedObject.ShouldBeEquivalentTo(expectedObject);
         }
+
+        public static IEnumerable<object[]> WriteDateTimeAsJsonTestCases()
+        {
+            yield return new object[]
+            {
+                new DateTimeOffset(2018, 1, 1, 10, 20, 30, TimeSpan.Zero),
+            };
+
+            yield return new object[]
+            {
+                new DateTimeOffset(2018, 1, 1, 10, 20, 30, 100, TimeSpan.FromHours(14)),
+            };
+
+            yield return new object[]
+            {
+                DateTimeOffset.UtcNow + TimeSpan.FromDays(4)
+            };
+
+            yield return new object[]
+            {
+                DateTime.UtcNow + TimeSpan.FromDays(4)
+            };
+        }
+
+        [Theory]
+        [MemberData(nameof(WriteDateTimeAsJsonTestCases))]
+        public void WriteDateTimeAsJsonShouldMatchExpected(DateTimeOffset dateTimeOffset)
+        {
+            // Arrange
+            var outputString = new StringWriter();
+            var writer = new OpenApiJsonWriter(outputString);
+
+            // Act
+            writer.WriteValue(dateTimeOffset);
+
+            var writtenString = outputString.GetStringBuilder().ToString();
+            var expectedString = JsonConvert.SerializeObject(dateTimeOffset, new JsonSerializerSettings
+            {
+                DateFormatString = "yyyy-MM-ddTHH:mm:ss.fffffffK",
+            });
+
+            // Assert
+            writtenString.Should().Be(expectedString);
+        }
     }
 }
\ No newline at end of file
diff --git a/test/Microsoft.OpenApi.Tests/Writers/OpenApiWriterAnyExtensionsTests.cs b/test/Microsoft.OpenApi.Tests/Writers/OpenApiWriterAnyExtensionsTests.cs
index 9ad1aa322..cefc1e486 100644
--- a/test/Microsoft.OpenApi.Tests/Writers/OpenApiWriterAnyExtensionsTests.cs
+++ b/test/Microsoft.OpenApi.Tests/Writers/OpenApiWriterAnyExtensionsTests.cs
@@ -97,9 +97,10 @@ public void WriteOpenApiDateTimeAsJsonWorks(string inputString)
             var dateTimeValue = new OpenApiDateTime(input);
 
             var json = WriteAsJson(dateTimeValue);
+            var expectedJson = "\"" + input.ToString("o") + "\"";
 
             // Assert
-            json.Should().Be(input.ToString("o"));
+            json.Should().Be(expectedJson);
         }
 
         [Theory]
diff --git a/test/Microsoft.OpenApi.Tests/Writers/OpenApiYamlWriterTests.cs b/test/Microsoft.OpenApi.Tests/Writers/OpenApiYamlWriterTests.cs
index 757f9097b..ab26191c5 100644
--- a/test/Microsoft.OpenApi.Tests/Writers/OpenApiYamlWriterTests.cs
+++ b/test/Microsoft.OpenApi.Tests/Writers/OpenApiYamlWriterTests.cs
@@ -1,6 +1,7 @@
 // Copyright (c) Microsoft Corporation. All rights reserved.
 // Licensed under the MIT license. 
 
+using System;
 using System.Collections;
 using System.Collections.Generic;
 using System.IO;
@@ -171,6 +172,20 @@ public static IEnumerable<object[]> WriteMapAsYamlShouldMatchExpectedTestCasesCo
 property11: ''"
             };
 
+            // DateTime
+            yield return new object[]
+            {
+                new Dictionary<string, object>
+                {
+                    ["property1"] = new DateTime(1970, 01, 01),
+                    ["property2"] = new DateTimeOffset(new DateTime(1970, 01, 01), TimeSpan.FromHours(3)),
+                    ["property3"] = new DateTime(2018, 04, 03),
+                },
+                @"property1: '1970-01-01T00:00:00.0000000'
+property2: '1970-01-01T00:00:00.0000000+03:00'
+property3: '2018-04-03T00:00:00.0000000'"
+            };
+
             // Nested map
             yield return new object[]
             {
@@ -237,13 +252,18 @@ public static IEnumerable<object[]> WriteMapAsYamlShouldMatchExpectedTestCasesCo
 
         private void WriteValueRecursive(OpenApiYamlWriter writer, object value)
         {
-            if (value == null || value.GetType().IsPrimitive || value is decimal || value is string)
+            if (value == null
+                || value.GetType().IsPrimitive
+                || value is decimal
+                || value is string
+                || value is DateTimeOffset
+                || value is DateTime)
             {
                 writer.WriteValue(value);
             }
             else if (value.GetType().IsGenericType &&
                 (typeof(IDictionary<,>).IsAssignableFrom(value.GetType().GetGenericTypeDefinition()) ||
-                    typeof(Dictionary<,>).IsAssignableFrom(value.GetType().GetGenericTypeDefinition())))
+                    typeof(Dictionary<,>).IsAssignableFrom(value.GetType().GetGenericTypeDefinition()) ) )
             {
                 writer.WriteStartObject();
                 foreach (var elementValue in (dynamic)(value))
@@ -284,5 +304,46 @@ public void WriteMapAsYamlShouldMatchExpected(IDictionary<string, object> inputM
             expectedYaml = expectedYaml.MakeLineBreaksEnvironmentNeutral();
             actualYaml.Should().Be(expectedYaml);
         }
+
+        public static IEnumerable<object[]> WriteDateTimeAsJsonTestCases()
+        {
+            yield return new object[]
+            {
+                new DateTimeOffset(2018, 1, 1, 10, 20, 30, TimeSpan.Zero)
+            };
+
+            yield return new object[]
+            {
+                new DateTimeOffset(2018, 1, 1, 10, 20, 30, 100, TimeSpan.FromHours(14))
+            };
+
+            yield return new object[]
+            {
+                DateTimeOffset.UtcNow + TimeSpan.FromDays(4)
+            };
+
+            yield return new object[]
+            {
+                DateTime.UtcNow + TimeSpan.FromDays(4)
+            };
+        }
+
+        [Theory]
+        [MemberData(nameof(WriteDateTimeAsJsonTestCases))]
+        public void WriteDateTimeAsJsonShouldMatchExpected(DateTimeOffset dateTimeOffset)
+        {
+            // Arrange
+            var outputString = new StringWriter();
+            var writer = new OpenApiYamlWriter(outputString);
+
+            // Act
+            writer.WriteValue(dateTimeOffset);
+
+            var writtenString = outputString.GetStringBuilder().ToString();
+            var expectedString = " '" + dateTimeOffset.ToString("o") + "'";
+
+            // Assert
+            writtenString.Should().Be(expectedString);
+        }
     }
 }
\ No newline at end of file