diff --git a/src/libstd/ascii.rs b/src/libstd/ascii.rs
index 2730d90f05f..fae1b933210 100644
--- a/src/libstd/ascii.rs
+++ b/src/libstd/ascii.rs
@@ -10,6 +10,8 @@
 
 //! Operations on ASCII strings and characters
 
+#![experimental]
+
 use collections::Collection;
 use fmt;
 use iter::Iterator;
diff --git a/src/libstd/bitflags.rs b/src/libstd/bitflags.rs
index 7d821983075..834d461f20b 100644
--- a/src/libstd/bitflags.rs
+++ b/src/libstd/bitflags.rs
@@ -105,6 +105,7 @@
 //! - `insert`: inserts the specified flags in-place
 //! - `remove`: removes the specified flags in-place
 
+#![experimental]
 #![macro_escape]
 
 #[macro_export]
diff --git a/src/libstd/c_vec.rs b/src/libstd/c_vec.rs
index 1926d6b1b96..a7d697c8665 100644
--- a/src/libstd/c_vec.rs
+++ b/src/libstd/c_vec.rs
@@ -33,6 +33,8 @@
 //! handled correctly, i.e. that allocated memory is eventually freed
 //! if necessary.
 
+#![experimental]
+
 use collections::Collection;
 use kinds::Send;
 use mem;
diff --git a/src/libstd/collections/mod.rs b/src/libstd/collections/mod.rs
index 9e5288f9541..ccef1c0fd2a 100644
--- a/src/libstd/collections/mod.rs
+++ b/src/libstd/collections/mod.rs
@@ -12,6 +12,8 @@
  * Collection types.
  */
 
+#![experimental]
+
 pub use core_collections::{Collection, Mutable, Map, MutableMap};
 pub use core_collections::{Set, MutableSet, Deque};
 pub use core_collections::{Bitv, BitvSet, BTree, DList, EnumSet};
diff --git a/src/libstd/failure.rs b/src/libstd/failure.rs
index d1552f0bd10..47ff85e2806 100644
--- a/src/libstd/failure.rs
+++ b/src/libstd/failure.rs
@@ -8,6 +8,8 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+#![experimental]
+
 use alloc::owned::Box;
 use any::{Any, AnyRefExt};
 use fmt;
diff --git a/src/libstd/fmt.rs b/src/libstd/fmt.rs
index ef0c59268c3..5834e576b08 100644
--- a/src/libstd/fmt.rs
+++ b/src/libstd/fmt.rs
@@ -412,6 +412,8 @@ the `}` character is escaped with `}}`.
 
 */
 
+#![experimental]
+
 use io::Writer;
 use io;
 use result::{Ok, Err};
diff --git a/src/libstd/from_str.rs b/src/libstd/from_str.rs
index 642bec48b83..1ca72bca20b 100644
--- a/src/libstd/from_str.rs
+++ b/src/libstd/from_str.rs
@@ -10,6 +10,8 @@
 
 //! The `FromStr` trait for types that can be created from strings
 
+#![experimental]
+
 use option::{Option, Some, None};
 use string::String;
 use str::StrAllocating;
diff --git a/src/libstd/gc.rs b/src/libstd/gc.rs
index 80f1cbe6cb2..47b7426633c 100644
--- a/src/libstd/gc.rs
+++ b/src/libstd/gc.rs
@@ -16,6 +16,7 @@ collector is task-local so `Gc<T>` is not sendable.
 
 */
 
+#![experimental]
 #![allow(experimental)]
 
 use clone::Clone;
diff --git a/src/libstd/io/mod.rs b/src/libstd/io/mod.rs
index 8014759c88a..1d339b03af6 100644
--- a/src/libstd/io/mod.rs
+++ b/src/libstd/io/mod.rs
@@ -216,6 +216,7 @@ responding to errors that may occur while attempting to read the numbers.
 
 */
 
+#![experimental]
 #![deny(unused_must_use)]
 
 use char::Char;
diff --git a/src/libstd/lib.rs b/src/libstd/lib.rs
index f63e69f3cca..48ccd1aa22c 100644
--- a/src/libstd/lib.rs
+++ b/src/libstd/lib.rs
@@ -95,6 +95,7 @@
 //! and `format!`, also available to all Rust code.
 
 #![crate_id = "std#0.11.0-pre"]
+#![unstable]
 #![comment = "The Rust standard library"]
 #![license = "MIT/ASL2"]
 #![crate_type = "rlib"]
diff --git a/src/libstd/macros.rs b/src/libstd/macros.rs
index 4db15d2cbbe..8b79af8c931 100644
--- a/src/libstd/macros.rs
+++ b/src/libstd/macros.rs
@@ -14,6 +14,7 @@
 //! library. Each macro is available for use when linking against the standard
 //! library.
 
+#![experimental]
 #![macro_escape]
 
 /// The entry point for failure of rust tasks.
diff --git a/src/libstd/num/f32.rs b/src/libstd/num/f32.rs
index bbf1458da21..2b2ffb9f4e2 100644
--- a/src/libstd/num/f32.rs
+++ b/src/libstd/num/f32.rs
@@ -10,6 +10,7 @@
 
 //! Operations and constants for 32-bits floats (`f32` type)
 
+#![experimental]
 #![allow(missing_doc)]
 #![allow(unsigned_negate)]
 #![doc(primitive = "f32")]
diff --git a/src/libstd/num/f64.rs b/src/libstd/num/f64.rs
index cfa8534160b..e156d2ce553 100644
--- a/src/libstd/num/f64.rs
+++ b/src/libstd/num/f64.rs
@@ -10,6 +10,7 @@
 
 //! Operations and constants for 64-bits floats (`f64` type)
 
+#![experimental]
 #![allow(missing_doc)]
 #![doc(primitive = "f64")]
 
diff --git a/src/libstd/num/float_macros.rs b/src/libstd/num/float_macros.rs
index 3e403219a4f..519de85edde 100644
--- a/src/libstd/num/float_macros.rs
+++ b/src/libstd/num/float_macros.rs
@@ -8,6 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+#![experimental]
 #![macro_escape]
 #![doc(hidden)]
 
diff --git a/src/libstd/num/int_macros.rs b/src/libstd/num/int_macros.rs
index 9b3c9d29cc7..a4200b55a59 100644
--- a/src/libstd/num/int_macros.rs
+++ b/src/libstd/num/int_macros.rs
@@ -8,6 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+#![experimental]
 #![macro_escape]
 #![doc(hidden)]
 
diff --git a/src/libstd/num/mod.rs b/src/libstd/num/mod.rs
index 65056652e3f..27ee1e3ce3b 100644
--- a/src/libstd/num/mod.rs
+++ b/src/libstd/num/mod.rs
@@ -13,6 +13,7 @@
 //! These are implemented for the primitive numeric types in `std::{u8, u16,
 //! u32, u64, uint, i8, i16, i32, i64, int, f32, f64}`.
 
+#![experimental]
 #![allow(missing_doc)]
 
 use option::Option;
diff --git a/src/libstd/num/uint_macros.rs b/src/libstd/num/uint_macros.rs
index 19e45b292fb..7f2efe034a2 100644
--- a/src/libstd/num/uint_macros.rs
+++ b/src/libstd/num/uint_macros.rs
@@ -8,6 +8,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
+#![experimental]
 #![macro_escape]
 #![doc(hidden)]
 #![allow(unsigned_negate)]
diff --git a/src/libstd/os.rs b/src/libstd/os.rs
index 5201a811791..6674dd532ae 100644
--- a/src/libstd/os.rs
+++ b/src/libstd/os.rs
@@ -26,6 +26,8 @@
  * to write OS-ignorant code by default.
  */
 
+#![experimental]
+
 #![allow(missing_doc)]
 #![allow(non_snake_case_functions)]
 
diff --git a/src/libstd/path/mod.rs b/src/libstd/path/mod.rs
index 6d48122b186..7d814df8ebf 100644
--- a/src/libstd/path/mod.rs
+++ b/src/libstd/path/mod.rs
@@ -63,6 +63,8 @@ println!("path exists: {}", path.exists());
 
 */
 
+#![experimental]
+
 use collections::Collection;
 use c_str::CString;
 use clone::Clone;
diff --git a/src/libstd/prelude.rs b/src/libstd/prelude.rs
index dfe6988624e..61e8b63af35 100644
--- a/src/libstd/prelude.rs
+++ b/src/libstd/prelude.rs
@@ -37,6 +37,8 @@
 //! particularly useful standalone functions, like `from_str`, `range`, and
 //! `drop`, `spawn`, and `channel`.
 
+#![experimental]
+
 // Reexported core operators
 #[doc(no_inline)] pub use kinds::{Copy, Send, Sized, Share};
 #[doc(no_inline)] pub use ops::{Add, Sub, Mul, Div, Rem, Neg, Not};
diff --git a/src/libstd/rand/mod.rs b/src/libstd/rand/mod.rs
index f48d487461e..0ffaadef0a1 100644
--- a/src/libstd/rand/mod.rs
+++ b/src/libstd/rand/mod.rs
@@ -73,6 +73,8 @@ println!("{}", tuple)
 ```
 */
 
+#![experimental]
+
 use cell::RefCell;
 use clone::Clone;
 use io::IoResult;
diff --git a/src/libstd/rt/mod.rs b/src/libstd/rt/mod.rs
index 19853138afd..4490977bde6 100644
--- a/src/libstd/rt/mod.rs
+++ b/src/libstd/rt/mod.rs
@@ -51,6 +51,8 @@ Several modules in `core` are clients of `rt`:
 
 */
 
+#![experimental]
+
 // FIXME: this should not be here.
 #![allow(missing_doc)]
 
diff --git a/src/libstd/rtdeps.rs b/src/libstd/rtdeps.rs
index f8bfde52261..0ffac99775c 100644
--- a/src/libstd/rtdeps.rs
+++ b/src/libstd/rtdeps.rs
@@ -12,6 +12,8 @@
 //! the standard library This varies per-platform, but these libraries are
 //! necessary for running libstd.
 
+#![experimental]
+
 // All platforms need to link to rustrt
 #[link(name = "rust_builtin", kind = "static")]
 extern {}
diff --git a/src/libstd/sync/mod.rs b/src/libstd/sync/mod.rs
index 5f45ce25502..cc32818baa4 100644
--- a/src/libstd/sync/mod.rs
+++ b/src/libstd/sync/mod.rs
@@ -15,6 +15,8 @@
 //! and/or blocking at all, but rather provide the necessary tools to build
 //! other types of concurrent primitives.
 
+#![experimental]
+
 pub use core_sync::{atomics, deque, mpmc_bounded_queue, mpsc_queue, spsc_queue};
 pub use core_sync::{Arc, Weak, Mutex, MutexGuard, Condvar, Barrier};
 pub use core_sync::{RWLock, RWLockReadGuard, RWLockWriteGuard};
diff --git a/src/libstd/task.rs b/src/libstd/task.rs
index 6492717d3ec..c20cbea0ae7 100644
--- a/src/libstd/task.rs
+++ b/src/libstd/task.rs
@@ -91,6 +91,8 @@
 //! # }
 //! ```
 
+#![experimental]
+
 use any::Any;
 use comm::channel;
 use io::{Writer, stdio};
diff --git a/src/libstd/to_str.rs b/src/libstd/to_str.rs
index 5deb7f151bb..e51e2c4d9ce 100644
--- a/src/libstd/to_str.rs
+++ b/src/libstd/to_str.rs
@@ -14,6 +14,8 @@ The `ToStr` trait for converting to strings
 
 */
 
+#![experimental]
+
 use fmt;
 use string::String;