diff --git a/lib/absinthe/blueprint/schema/enum_type_definition.ex b/lib/absinthe/blueprint/schema/enum_type_definition.ex
index 7afbb43248..59951c605f 100644
--- a/lib/absinthe/blueprint/schema/enum_type_definition.ex
+++ b/lib/absinthe/blueprint/schema/enum_type_definition.ex
@@ -29,6 +29,7 @@ defmodule Absinthe.Blueprint.Schema.EnumTypeDefinition do
           flags: Blueprint.flags_t(),
           errors: [Absinthe.Phase.Error.t()]
         }
+
   def build(type_def, _schema) do
     %Absinthe.Type.Enum{
       identifier: type_def.identifier,
diff --git a/lib/absinthe/schema/notation/sdl_render.ex b/lib/absinthe/schema/notation/sdl_render.ex
index 83496b2d5b..e7fb38b700 100644
--- a/lib/absinthe/schema/notation/sdl_render.ex
+++ b/lib/absinthe/schema/notation/sdl_render.ex
@@ -103,11 +103,43 @@ defmodule Absinthe.Schema.Notation.SDL.Render do
 
   @adapter Absinthe.Adapter.LanguageConventions
   defp render(%Blueprint.Schema.InputValueDefinition{} = input_value, type_definitions) do
+    default_value =
+      case input_value.default_value do
+        nil ->
+          nil
+
+        value when is_atom(value) ->
+          typ =
+            case input_value.type do
+              %Absinthe.Blueprint.TypeReference.NonNull{of_type: t} -> t
+              %Absinthe.Blueprint.TypeReference.List{of_type: t} -> t
+              t -> t
+            end
+
+          definition = Enum.find(type_definitions, fn d -> typ == d.identifier end)
+
+          case definition do
+            nil ->
+              value
+
+            _ ->
+              enum = Absinthe.Blueprint.Schema.EnumTypeDefinition.build(definition, nil)
+
+              %Blueprint.Input.Enum{
+                value: Absinthe.Type.Enum.serialize(enum, value),
+                source_location: input_value.source_location
+              }
+          end
+
+        value ->
+          Blueprint.Input.parse(value)
+      end
+
     concat([
       string(@adapter.to_external_name(input_value.name, :argument)),
       ": ",
       render(input_value.type, type_definitions),
-      default(input_value.default_value_blueprint),
+      default(input_value.default_value_blueprint || default_value),
       directives(input_value.directives, type_definitions)
     ])
     |> description(input_value.description)
@@ -342,6 +374,10 @@ defmodule Absinthe.Schema.Notation.SDL.Render do
     empty()
   end
 
+  defp default(%{value: nil}) do
+    empty()
+  end
+
   defp default(default_value) do
     concat([" = ", render_value(default_value)])
   end
diff --git a/test/absinthe/schema/sdl_render_test.exs b/test/absinthe/schema/sdl_render_test.exs
index f9d27f3df8..cb4e584ba9 100644
--- a/test/absinthe/schema/sdl_render_test.exs
+++ b/test/absinthe/schema/sdl_render_test.exs
@@ -197,6 +197,8 @@ defmodule Absinthe.Schema.SdlRenderTest do
       field :echo, :string do
         arg :times, :integer, default_value: 10, description: "The number of times"
         arg :time_interval, :integer
+        arg :time_string, :string, default_value: "2021"
+        arg :order_status, non_null(:order_status), default_value: :processing
       end
 
       field :search, :search_result
@@ -251,9 +253,13 @@ defmodule Absinthe.Schema.SdlRenderTest do
              type RootQueryType {
                echo(
                  "The number of times"
-                 times: Int
+                 times: Int = 10
 
                  timeInterval: Int
+
+                 timeString: String = "2021"
+
+                 orderStatus: OrderStatus! = PROCESSING
                ): String
                search: SearchResult
              }