diff --git a/test/Swashbuckle.AspNetCore.Newtonsoft.Test/Fixtures/JsonObjectAnnotatedType.cs b/test/Swashbuckle.AspNetCore.Newtonsoft.Test/Fixtures/JsonObjectAnnotatedType.cs
index c3385cb49d..24d1ba005c 100644
--- a/test/Swashbuckle.AspNetCore.Newtonsoft.Test/Fixtures/JsonObjectAnnotatedType.cs
+++ b/test/Swashbuckle.AspNetCore.Newtonsoft.Test/Fixtures/JsonObjectAnnotatedType.cs
@@ -1,8 +1,10 @@
-using Newtonsoft.Json;
+using System.Runtime.Serialization;
+using Newtonsoft.Json;
 
 namespace Swashbuckle.AspNetCore.Newtonsoft.Test
 {
     [JsonObject(ItemRequired = Required.Always)]
+    [DataContract]
     public class JsonObjectAnnotatedType
     {
         public string StringWithNoAnnotation { get; set; }
@@ -12,5 +14,8 @@ public class JsonObjectAnnotatedType
 
         [JsonProperty(Required = Required.AllowNull)]
         public string StringWithRequiredAllowNull { get; set; }
+
+        [DataMember(IsRequired = false)]
+        public string StringWithDataMemberRequiredFalse { get; set; }
     }
 }
diff --git a/test/Swashbuckle.AspNetCore.Newtonsoft.Test/Fixtures/JsonPropertyAnnotatedType.cs b/test/Swashbuckle.AspNetCore.Newtonsoft.Test/Fixtures/JsonPropertyAnnotatedType.cs
index c50f2bbee0..7c6fa798e8 100644
--- a/test/Swashbuckle.AspNetCore.Newtonsoft.Test/Fixtures/JsonPropertyAnnotatedType.cs
+++ b/test/Swashbuckle.AspNetCore.Newtonsoft.Test/Fixtures/JsonPropertyAnnotatedType.cs
@@ -1,7 +1,9 @@
-using Newtonsoft.Json;
+using System.Runtime.Serialization;
+using Newtonsoft.Json;
 
 namespace Swashbuckle.AspNetCore.Newtonsoft.Test
 {
+    [DataContract]
     public class JsonPropertyAnnotatedType
     {
         [JsonProperty("string-with-json-property-name")]
@@ -21,5 +23,13 @@ public class JsonPropertyAnnotatedType
 
         [JsonProperty(Required = Required.AllowNull)]
         public string StringWithRequiredAllowNull { get; set; }
+
+        [DataMember(IsRequired = false)] //As the support for DataMember has been implemented later, JsonRequired should take precedence
+        [JsonProperty(Required = Required.Always)]
+        public string StringWithRequiredAlwaysButConflictingDataMember { get; set; }
+
+        [DataMember(IsRequired = true)] //As the support for DataMember has been implemented later, JsonRequired should take precedence
+        [JsonProperty(Required = Required.Default)]
+        public string StringWithRequiredDefaultButConflictingDataMember { get; set; }
     }
 }
\ No newline at end of file
diff --git a/test/Swashbuckle.AspNetCore.Newtonsoft.Test/Fixtures/JsonRequiredAnnotatedType.cs b/test/Swashbuckle.AspNetCore.Newtonsoft.Test/Fixtures/JsonRequiredAnnotatedType.cs
index 1709b237f6..ad4584cda4 100644
--- a/test/Swashbuckle.AspNetCore.Newtonsoft.Test/Fixtures/JsonRequiredAnnotatedType.cs
+++ b/test/Swashbuckle.AspNetCore.Newtonsoft.Test/Fixtures/JsonRequiredAnnotatedType.cs
@@ -1,10 +1,16 @@
-using Newtonsoft.Json;
+using System.Runtime.Serialization;
+using Newtonsoft.Json;
 
 namespace Swashbuckle.AspNetCore.Newtonsoft.Test
 {
+    [DataContract]
     public class JsonRequiredAnnotatedType
     {
         [JsonRequired]
         public string StringWithJsonRequired { get; set; }
+
+        [DataMember(IsRequired = false)] //As the support for DataMember has been implemented later, JsonRequired should take precedence
+        [JsonRequired]
+        public string StringWithConflictingRequired { get; set; }
     }
 }
\ No newline at end of file
diff --git a/test/Swashbuckle.AspNetCore.Newtonsoft.Test/SchemaGenerator/NewtonsoftSchemaGeneratorTests.cs b/test/Swashbuckle.AspNetCore.Newtonsoft.Test/SchemaGenerator/NewtonsoftSchemaGeneratorTests.cs
index ed2b4b9612..1ff8248ac3 100644
--- a/test/Swashbuckle.AspNetCore.Newtonsoft.Test/SchemaGenerator/NewtonsoftSchemaGeneratorTests.cs
+++ b/test/Swashbuckle.AspNetCore.Newtonsoft.Test/SchemaGenerator/NewtonsoftSchemaGeneratorTests.cs
@@ -755,6 +755,8 @@ public void GenerateSchema_HonorsSerializerAttribute_JsonProperty()
                     "StringWithRequiredDisallowNull",
                     "StringWithRequiredAlways",
                     "StringWithRequiredAllowNull",
+                    "StringWithRequiredAlwaysButConflictingDataMember",
+                    "StringWithRequiredDefaultButConflictingDataMember"
                 },
                 schema.Properties.Keys.ToArray()
             );
@@ -762,7 +764,8 @@ public void GenerateSchema_HonorsSerializerAttribute_JsonProperty()
                 new[]
                 {
                     "StringWithRequiredAllowNull",
-                    "StringWithRequiredAlways"
+                    "StringWithRequiredAlways",
+                    "StringWithRequiredAlwaysButConflictingDataMember"
                 },
                 schema.Required.ToArray()
             );
@@ -772,6 +775,8 @@ public void GenerateSchema_HonorsSerializerAttribute_JsonProperty()
             Assert.False(schema.Properties["StringWithRequiredDisallowNull"].Nullable);
             Assert.False(schema.Properties["StringWithRequiredAlways"].Nullable);
             Assert.True(schema.Properties["StringWithRequiredAllowNull"].Nullable);
+            Assert.False(schema.Properties["StringWithRequiredAlwaysButConflictingDataMember"].Nullable);
+            Assert.True(schema.Properties["StringWithRequiredDefaultButConflictingDataMember"].Nullable);
         }
 
         [Fact]
@@ -782,7 +787,7 @@ public void GenerateSchema_HonorsSerializerAttribute_JsonRequired()
             var referenceSchema = Subject().GenerateSchema(typeof(JsonRequiredAnnotatedType), schemaRepository);
 
             var schema = schemaRepository.Schemas[referenceSchema.Reference.Id];
-            Assert.Equal(new[] { "StringWithJsonRequired" }, schema.Required.ToArray());
+            Assert.Equal(new[] { "StringWithConflictingRequired", "StringWithJsonRequired"}, schema.Required.ToArray());
             Assert.False(schema.Properties["StringWithJsonRequired"].Nullable);
         }
 
@@ -797,6 +802,7 @@ public void GenerateSchema_HonorsSerializerAttribute_JsonObject()
             Assert.Equal(
                 new[]
                 {
+                    "StringWithDataMemberRequiredFalse",
                     "StringWithNoAnnotation",
                     "StringWithRequiredAllowNull",
                     "StringWithRequiredUnspecified"
@@ -806,6 +812,7 @@ public void GenerateSchema_HonorsSerializerAttribute_JsonObject()
             Assert.False(schema.Properties["StringWithNoAnnotation"].Nullable);
             Assert.False(schema.Properties["StringWithRequiredUnspecified"].Nullable);
             Assert.True(schema.Properties["StringWithRequiredAllowNull"].Nullable);
+            Assert.False(schema.Properties["StringWithDataMemberRequiredFalse"].Nullable);
         }
 
         [Fact]