diff --git a/lib/unifex/code_generator/base_types/int64.ex b/lib/unifex/code_generator/base_types/int64.ex
index aecad51..a65c7de 100644
--- a/lib/unifex/code_generator/base_types/int64.ex
+++ b/lib/unifex/code_generator/base_types/int64.ex
@@ -12,4 +12,19 @@ defmodule Unifex.CodeGenerator.BaseTypes.Int64 do
   def generate_native_type(_ctx) do
     ~g<int64_t>
   end
+
+  defmodule NIF do
+    @moduledoc false
+    use Unifex.CodeGenerator.BaseType
+
+    @impl true
+    def generate_arg_parse(argument, variable, _ctx) do
+      ~g<({
+        ErlNifSInt64 temp = 0;
+        int success = enif_get_int64(env, #{argument}, &temp);
+        #{variable} = (int64_t)temp;
+        success;
+        })>
+    end
+  end
 end