diff --git a/src/decoders_deriver.ml b/src/decoders_deriver.ml
index e4c6b7c..7a95ab5 100644
--- a/src/decoders_deriver.ml
+++ b/src/decoders_deriver.ml
@@ -67,13 +67,21 @@ let rec expr_of_typ (typ : core_type)
   match typ with
   | [%type: unit] | [%type: unit] -> Ast_builder.Default.evar ~loc "D.null"
   | [%type: int] -> Ast_builder.Default.evar ~loc "D.int"
-  | [%type: int32]
-  | [%type: Int32.t]
-  | [%type: int64]
-  | [%type: Int64.t]
-  | [%type: nativeint]
-  | [%type: Nativeint.t] ->
-      failwith "Cannot yet handle any int-like but int"
+  | [%type: int32] | [%type: Int32.t] ->
+      let int_dec = Ast_builder.Default.evar ~loc "D.int" in
+      [%expr
+        let open D.Infix in
+        [%e int_dec] >|= Int32.of_int]
+  | [%type: int64] | [%type: Int64.t] ->
+      let int_dec = Ast_builder.Default.evar ~loc "D.int" in
+      [%expr
+        let open D.Infix in
+        [%e int_dec] >|= Int64.of_int]
+  | [%type: nativeint] | [%type: Nativeint.t] ->
+      let int_dec = Ast_builder.Default.evar ~loc "D.int" in
+      [%expr
+        let open D.Infix in
+        [%e int_dec] >|= Nativeint.of_int]
   | [%type: float] -> Ast_builder.Default.evar ~loc "D.float"
   | [%type: bool] -> Ast_builder.Default.evar ~loc "D.bool"
   | [%type: char] ->
diff --git a/src/encoders_deriver.ml b/src/encoders_deriver.ml
index 0692f0e..7aebbe2 100644
--- a/src/encoders_deriver.ml
+++ b/src/encoders_deriver.ml
@@ -20,13 +20,15 @@ let rec expr_of_typ (typ : core_type) : expression =
   match typ with
   | [%type: unit] | [%type: unit] -> Ast_builder.Default.evar ~loc "E.null"
   | [%type: int] -> Ast_builder.Default.evar ~loc "E.int"
-  | [%type: int32]
-  | [%type: Int32.t]
-  | [%type: int64]
-  | [%type: Int64.t]
-  | [%type: nativeint]
-  | [%type: Nativeint.t] ->
-      failwith "Cannot yet handle any int-like but int"
+  | [%type: int32] | [%type: Int32.t] ->
+      let int_enc = Ast_builder.Default.evar ~loc "E.int" in
+      [%expr fun i -> i |> Int32.to_int |> [%e int_enc]]
+  | [%type: int64] | [%type: Int64.t] ->
+      let int_enc = Ast_builder.Default.evar ~loc "E.int" in
+      [%expr fun i -> i |> Int64.to_int |> [%e int_enc]]
+  | [%type: nativeint] | [%type: Nativeint.t] ->
+      let int_enc = Ast_builder.Default.evar ~loc "E.int" in
+      [%expr fun i -> i |> Nativeint.to_int |> [%e int_enc]]
   | [%type: float] -> Ast_builder.Default.evar ~loc "E.float"
   | [%type: bool] -> Ast_builder.Default.evar ~loc "E.bool"
   | [%type: char] ->
diff --git a/test/test_decoders.ml b/test/test_decoders.ml
index 169574c..fde8e90 100644
--- a/test/test_decoders.ml
+++ b/test/test_decoders.ml
@@ -273,3 +273,40 @@ let%test "double type var" =
   match D.decode_string double_wrapped_decoder {|{"fst":"99","snd":100}|} with
   | Ok { fst = "99"; snd = 100 } -> true
   | _ -> false
+
+module Ints = struct
+  type my_int32 = int32 [@@deriving decoders]
+
+  let%test "int32" =
+    match D.decode_string my_int32_decoder "123445" with
+    | Ok 123445l -> true
+    | _ -> false
+
+  type my_int32t = Int32.t [@@deriving decoders]
+
+  let%test "int32t" =
+    match D.decode_string my_int32t_decoder "5438" with
+    | Ok 5438l -> true
+    | _ -> false
+
+  type my_int64 = int64 [@@deriving decoders]
+
+  let%test "int64" =
+    match D.decode_string my_int64_decoder "123445" with
+    | Ok 123445L -> true
+    | _ -> false
+
+  type my_int64t = Int64.t [@@deriving decoders]
+
+  let%test "int64t" =
+    match D.decode_string my_int64t_decoder "5438" with
+    | Ok 5438L -> true
+    | _ -> false
+
+  type my_nativeint = Nativeint.t [@@deriving decoders]
+
+  let%test "my_nativeint" =
+    match D.decode_string my_nativeint_decoder "5438" with
+    | Ok 5438n -> true
+    | _ -> false
+end
diff --git a/test/test_encoders.ml b/test/test_encoders.ml
index aeab430..605907d 100644
--- a/test/test_encoders.ml
+++ b/test/test_encoders.ml
@@ -98,3 +98,40 @@ let%test "module wrapped" =
   match E.encode_string outer_inner_wrapped_encoder { wrapped = "a thing" } with
   | {|{"wrapped":"a thing"}|} -> true
   | _ -> false
+
+module Ints = struct
+  type my_int32 = int32 [@@deriving encoders]
+
+  let%test "int32" =
+    match E.encode_string my_int32_encoder 123445l with
+    | "123445" -> true
+    | _ -> false
+
+  type my_int32t = Int32.t [@@deriving encoders]
+
+  let%test "int32t" =
+    match E.encode_string my_int32t_encoder 5438l with
+    | "5438" -> true
+    | _ -> false
+
+  type my_int64 = int64 [@@deriving encoders]
+
+  let%test "int64" =
+    match E.encode_string my_int64_encoder 123445L with
+    | "123445" -> true
+    | _ -> false
+
+  type my_int64t = Int64.t [@@deriving encoders]
+
+  let%test "int64t" =
+    match E.encode_string my_int64t_encoder 5438L with
+    | "5438" -> true
+    | _ -> false
+
+  type my_nativeint = Nativeint.t [@@deriving encoders]
+
+  let%test "my_nativeint" =
+    match E.encode_string my_nativeint_encoder 5438n with
+    | "5438" -> true
+    | _ -> false
+end