diff --git a/vm/src/stdlib/io.rs b/vm/src/stdlib/io.rs
new file mode 100644
index 000000000..d2bed51d5
--- /dev/null
+++ b/vm/src/stdlib/io.rs
@@ -0,0 +1,51 @@
+/*
+ * I/O core tools.
+ */
+
+// use super::super::obj::{objstr, objtype};
+use super::super::pyobject::{
+    AttributeProtocol, DictProtocol, PyContext, PyFuncArgs, PyObjectRef, PyResult,
+};
+use super::super::VirtualMachine;
+
+fn string_io_init(vm: &mut VirtualMachine, _args: PyFuncArgs) -> PyResult {
+    // arg_check!(vm, args, required = [(s, Some(vm.ctx.str_type()))]);
+    // TODO
+    Ok(vm.get_none())
+}
+
+fn string_io_getvalue(vm: &mut VirtualMachine, args: PyFuncArgs) -> PyResult {
+    arg_check!(vm, args);
+    // TODO
+    Ok(vm.get_none())
+}
+
+fn bytes_io_init(vm: &mut VirtualMachine, _args: PyFuncArgs) -> PyResult {
+    // TODO
+    Ok(vm.get_none())
+}
+
+fn bytes_io_getvalue(vm: &mut VirtualMachine, args: PyFuncArgs) -> PyResult {
+    arg_check!(vm, args);
+    // TODO
+    Ok(vm.get_none())
+}
+
+pub fn mk_module(ctx: &PyContext) -> PyObjectRef {
+    let py_mod = ctx.new_module(&"io".to_string(), ctx.new_scope(None));
+
+    let io_base = ctx.new_class("IOBase", ctx.object());
+    py_mod.set_item("IOBase", io_base.clone());
+
+    let string_io = ctx.new_class("StringIO", io_base.clone());
+    string_io.set_attr("__init__", ctx.new_rustfunc(string_io_init));
+    string_io.set_attr("getvalue", ctx.new_rustfunc(string_io_getvalue));
+    py_mod.set_item("StringIO", string_io);
+
+    let bytes_io = ctx.new_class("BytesIO", io_base.clone());
+    bytes_io.set_attr("__init__", ctx.new_rustfunc(bytes_io_init));
+    bytes_io.set_attr("getvalue", ctx.new_rustfunc(bytes_io_getvalue));
+    py_mod.set_item("BytesIO", bytes_io);
+
+    py_mod
+}
diff --git a/vm/src/stdlib/mod.rs b/vm/src/stdlib/mod.rs
index 1da9407d8..64a34d748 100644
--- a/vm/src/stdlib/mod.rs
+++ b/vm/src/stdlib/mod.rs
@@ -1,4 +1,5 @@
 mod ast;
+mod io;
 mod json;
 mod keyword;
 mod math;
@@ -10,6 +11,7 @@ pub type StdlibInitFunc = fn(&PyContext) -> PyObjectRef;
 
 pub fn get_module_inits() -> HashMap<String, StdlibInitFunc> {
     let mut modules = HashMap::new();
+    modules.insert("io".to_string(), io::mk_module as StdlibInitFunc);
     modules.insert("json".to_string(), json::mk_module as StdlibInitFunc);
     modules.insert("ast".to_string(), ast::mk_module as StdlibInitFunc);
     modules.insert("keyword".to_string(), keyword::mk_module as StdlibInitFunc);