diff --git a/example/example.g.dart b/example/example.g.dart
index 880685df..c8782934 100644
--- a/example/example.g.dart
+++ b/example/example.g.dart
@@ -22,7 +22,7 @@ abstract class _$PersonSerializerMixin {
   String get middleName;
   String get lastName;
   DateTime get dateOfBirth;
-  List get orders;
+  List<Order> get orders;
   Map<String, dynamic> toJson() => <String, dynamic>{
         'firstName': firstName,
         'middleName': middleName,
diff --git a/lib/generators/json_serializable_generator.dart b/lib/generators/json_serializable_generator.dart
index 16c7f205..e322a9a1 100644
--- a/lib/generators/json_serializable_generator.dart
+++ b/lib/generators/json_serializable_generator.dart
@@ -88,8 +88,7 @@ class JsonSerializableGenerator
       // write fields
       fields.forEach((name, field) {
         //TODO - handle aliased imports
-        //TODO - write generic types. Now `List<int>` turns into `List`
-        buffer.writeln('  ${field.type.name} get $name;');
+        buffer.writeln('  ${field.type} get $name;');
       });
 
       // write toJson method
@@ -204,26 +203,33 @@ class JsonSerializableGenerator
       }
     }
 
-    if (_coreListChecker.isAssignableFromType(fieldType)) {
-      var indexVal = "i${depth}";
-
-      var substitute = '${expression}[$indexVal]';
+    var isList = false;
+    if (_coreIterableChecker.isAssignableFromType(fieldType)) {
+      if (_coreListChecker.isAssignableFromType(fieldType)) {
+        isList = true;
+      }
+      var substitute = "v$depth";
       var subFieldValue = _fieldToJsonMapValue(substitute,
           _getIterableGenericType(fieldType as InterfaceType), depth + 1);
 
-      // If we're dealing with `List<T>` where `T` must be serialized, then
-      // generate a value that does the equivalent of .map(...).toList(), but
-      // Does so efficiently by creating a known-length List.
-      //TODO(kevmoo) this might be overkill. I think .map on iterable returns
-      //  an efficient-length iterable, so .map(...).toList() might be fine. :-/
+      // In the case of trivial JSON types (int, String, etc), `subFieldValue`
+      // will be identical to `substitute` – so no explicit mapping is needed.
+      // If they are not equal, then we to write out the substitution.
       if (subFieldValue != substitute) {
         // TODO: the type could be imported from a library with a prefix!
-        return "${expression} == null ? null : "
-            "new List.generate(${expression}.length, "
-            "(int $indexVal) => $subFieldValue)";
+        expression = "${expression}?.map(($substitute) => $subFieldValue)";
+
+        // expression now represents an Iterable (even if it started as a List
+        // ...resetting `isList` to `false`.
+        isList = false;
       }
     }
 
+    if (!isList && _coreIterableChecker.isAssignableFromType(fieldType)) {
+      // Then we need to add `?.toList()
+      expression += "?.toList()";
+    }
+
     return expression;
   }
 
@@ -252,6 +258,13 @@ class JsonSerializableGenerator
           _getIterableGenericType(searchType as InterfaceType);
 
       var itemVal = "v$depth";
+      var itemSubVal =
+          _writeAccessToVar(itemVal, iterableGenericType, depth: depth + 1);
+
+      // If `itemSubVal` is the same, then we don't need to do anything fancy
+      if (itemVal == itemSubVal) {
+        return varExpression;
+      }
 
       var output = "($varExpression as List)?.map(($itemVal) => "
           "${_writeAccessToVar(itemVal, iterableGenericType, depth: depth+1)}"
@@ -264,7 +277,7 @@ class JsonSerializableGenerator
       return output;
     }
 
-    if (!searchType.isDynamic) {
+    if (!searchType.isDynamic && !searchType.isObject) {
       return "$varExpression as $searchType";
     }
 
diff --git a/test/json_serializable_test.dart b/test/json_serializable_test.dart
index fc29dd31..a06a2dad 100644
--- a/test/json_serializable_test.dart
+++ b/test/json_serializable_test.dart
@@ -94,7 +94,7 @@ void main() {
           await _getClassForCodeString('ParentObjectWithDynamicChildren');
       var output = await _generator.generate(element, null);
 
-      expect(output, contains('(json[\'children\'] as List)?.map('));
+      expect(output, contains('children = json[\'children\'];'));
     });
 
     test('class with list of int is cast for strong mode', () async {
diff --git a/test/test_files/json_test_example.dart b/test/test_files/json_test_example.dart
index 09fa4d72..d420c410 100644
--- a/test/test_files/json_test_example.dart
+++ b/test/test_files/json_test_example.dart
@@ -11,6 +11,26 @@ import 'package:source_gen/generators/json_serializable.dart';
 
 part 'json_test_example.g.dart';
 
+@JsonSerializable()
+class ListGenericTests extends Object with _$ListGenericTestsSerializerMixin {
+  ListGenericTests();
+
+  factory ListGenericTests.fromJson(Map<String, Object> json) =>
+      _$ListGenericTestsFromJson(json);
+
+  Iterable iterable;
+  Iterable<dynamic> dynamicIterable;
+  Iterable<Object> objectIterable;
+  Iterable<int> intIterable;
+  Iterable<DateTime> dateTimeIterable;
+
+  List list;
+  List<dynamic> dynamicList;
+  List<Object> objectList;
+  List<int> intList;
+  List<DateTime> dateTimeList;
+}
+
 @JsonSerializable()
 class Person extends Object with _$PersonSerializerMixin {
   final String firstName, middleName, lastName;
diff --git a/test/test_files/json_test_example.g.dart b/test/test_files/json_test_example.g.dart
index 2adb3fa1..344832d5 100644
--- a/test/test_files/json_test_example.g.dart
+++ b/test/test_files/json_test_example.g.dart
@@ -2,6 +2,53 @@
 
 part of source_gen.test.example;
 
+// **************************************************************************
+// Generator: JsonSerializableGenerator
+// Target: class ListGenericTests
+// **************************************************************************
+
+ListGenericTests _$ListGenericTestsFromJson(Map json) => new ListGenericTests()
+  ..iterable = json['iterable']
+  ..dynamicIterable = json['dynamicIterable']
+  ..objectIterable = json['objectIterable']
+  ..intIterable = (json['intIterable'] as List)?.map((v0) => v0 as int)
+  ..dateTimeIterable = (json['dateTimeIterable'] as List)
+      ?.map((v0) => v0 == null ? null : DateTime.parse(v0))
+  ..list = json['list']
+  ..dynamicList = json['dynamicList']
+  ..objectList = json['objectList']
+  ..intList = (json['intList'] as List)?.map((v0) => v0 as int)?.toList()
+  ..dateTimeList = (json['dateTimeList'] as List)
+      ?.map((v0) => v0 == null ? null : DateTime.parse(v0))
+      ?.toList();
+
+abstract class _$ListGenericTestsSerializerMixin {
+  Iterable<dynamic> get iterable;
+  Iterable<dynamic> get dynamicIterable;
+  Iterable<Object> get objectIterable;
+  Iterable<int> get intIterable;
+  Iterable<DateTime> get dateTimeIterable;
+  List<dynamic> get list;
+  List<dynamic> get dynamicList;
+  List<Object> get objectList;
+  List<int> get intList;
+  List<DateTime> get dateTimeList;
+  Map<String, dynamic> toJson() => <String, dynamic>{
+        'iterable': iterable?.toList(),
+        'dynamicIterable': dynamicIterable?.toList(),
+        'objectIterable': objectIterable?.toList(),
+        'intIterable': intIterable?.toList(),
+        'dateTimeIterable':
+            dateTimeIterable?.map((v0) => v0?.toIso8601String())?.toList(),
+        'list': list,
+        'dynamicList': dynamicList,
+        'objectList': objectList,
+        'intList': intList,
+        'dateTimeList':
+            dateTimeList?.map((v0) => v0?.toIso8601String())?.toList()
+      };
+}
+
 // **************************************************************************
 // Generator: JsonSerializableGenerator
 // Target: class Person
@@ -40,7 +87,7 @@ Order _$OrderFromJson(Map json) => new Order((json['items'] as List)
 abstract class _$OrderSerializerMixin {
   int get count;
   bool get isRushed;
-  UnmodifiableListView get items;
+  UnmodifiableListView<Item> get items;
   Map<String, dynamic> toJson() =>
       <String, dynamic>{'count': count, 'isRushed': isRushed, 'items': items};
 }
@@ -60,15 +107,12 @@ Item _$ItemFromJson(Map json) => new Item(json['price'] as int)
 abstract class _$ItemSerializerMixin {
   int get price;
   int get itemNumber;
-  List get saleDates;
-  List get rates;
+  List<DateTime> get saleDates;
+  List<int> get rates;
   Map<String, dynamic> toJson() => <String, dynamic>{
         'price': price,
         'itemNumber': itemNumber,
-        'saleDates': saleDates == null
-            ? null
-            : new List.generate(
-                saleDates.length, (int i0) => saleDates[i0]?.toIso8601String()),
+        'saleDates': saleDates?.map((v0) => v0?.toIso8601String())?.toList(),
         'rates': rates
       };
 }