diff --git a/src/libcollections/lib.rs b/src/libcollections/lib.rs
index 4d0aaf83907..b74324c85c0 100644
--- a/src/libcollections/lib.rs
+++ b/src/libcollections/lib.rs
@@ -20,7 +20,7 @@
        html_playground_url = "http://play.rust-lang.org/")]
 
 #![allow(unknown_features)]
-#![feature(macro_rules, managed_boxes, default_type_params, phase, globs)]
+#![feature(macro_rules, default_type_params, phase, globs)]
 #![feature(unsafe_destructor, import_shadowing, slicing_syntax)]
 #![no_std]
 
diff --git a/src/libcore/lib.rs b/src/libcore/lib.rs
index 4890dc2bb73..584d09c75c8 100644
--- a/src/libcore/lib.rs
+++ b/src/libcore/lib.rs
@@ -58,7 +58,7 @@
 
 #![no_std]
 #![allow(unknown_features)]
-#![feature(globs, intrinsics, lang_items, macro_rules, managed_boxes, phase)]
+#![feature(globs, intrinsics, lang_items, macro_rules, phase)]
 #![feature(simd, unsafe_destructor, slicing_syntax)]
 #![deny(missing_doc)]
 
diff --git a/src/libdebug/lib.rs b/src/libdebug/lib.rs
index 6341a380563..21abfae8be9 100644
--- a/src/libdebug/lib.rs
+++ b/src/libdebug/lib.rs
@@ -25,7 +25,7 @@
        html_favicon_url = "http://www.rust-lang.org/favicon.ico",
        html_root_url = "http://doc.rust-lang.org/master/")]
 #![experimental]
-#![feature(managed_boxes, macro_rules)]
+#![feature(macro_rules)]
 #![allow(experimental)]
 
 pub mod fmt;
diff --git a/src/libfourcc/lib.rs b/src/libfourcc/lib.rs
index 3aa40058792..388373807d8 100644
--- a/src/libfourcc/lib.rs
+++ b/src/libfourcc/lib.rs
@@ -50,7 +50,7 @@ fn main() {
        html_favicon_url = "http://www.rust-lang.org/favicon.ico",
        html_root_url = "http://doc.rust-lang.org/master/")]
 
-#![feature(plugin_registrar, managed_boxes)]
+#![feature(plugin_registrar)]
 
 extern crate syntax;
 extern crate rustc;
diff --git a/src/libhexfloat/lib.rs b/src/libhexfloat/lib.rs
index ae7a3e66dfd..2fcc3b9691a 100644
--- a/src/libhexfloat/lib.rs
+++ b/src/libhexfloat/lib.rs
@@ -46,7 +46,7 @@ fn main() {
 #![doc(html_logo_url = "http://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
        html_favicon_url = "http://www.rust-lang.org/favicon.ico",
        html_root_url = "http://doc.rust-lang.org/master/")]
-#![feature(plugin_registrar, managed_boxes)]
+#![feature(plugin_registrar)]
 
 extern crate syntax;
 extern crate rustc;
diff --git a/src/libregex_macros/lib.rs b/src/libregex_macros/lib.rs
index 3535038b6a5..67018769fb3 100644
--- a/src/libregex_macros/lib.rs
+++ b/src/libregex_macros/lib.rs
@@ -19,7 +19,7 @@
        html_favicon_url = "http://www.rust-lang.org/favicon.ico",
        html_root_url = "http://doc.rust-lang.org/master/")]
 
-#![feature(plugin_registrar, managed_boxes, quote)]
+#![feature(plugin_registrar, quote)]
 
 extern crate regex;
 extern crate syntax;
diff --git a/src/librustdoc/lib.rs b/src/librustdoc/lib.rs
index b46d8727b69..77d63224fcd 100644
--- a/src/librustdoc/lib.rs
+++ b/src/librustdoc/lib.rs
@@ -16,7 +16,7 @@
 #![crate_type = "rlib"]
 
 #![allow(unknown_features)]
-#![feature(globs, struct_variant, managed_boxes, macro_rules, phase, slicing_syntax)]
+#![feature(globs, struct_variant, macro_rules, phase, slicing_syntax)]
 
 extern crate arena;
 extern crate debug;
diff --git a/src/librustrt/lib.rs b/src/librustrt/lib.rs
index ad1eac41e4d..d3ea07291a4 100644
--- a/src/librustrt/lib.rs
+++ b/src/librustrt/lib.rs
@@ -17,7 +17,7 @@
        html_root_url = "http://doc.rust-lang.org/master/")]
 
 #![allow(unknown_features)]
-#![feature(macro_rules, phase, globs, thread_local, managed_boxes, asm)]
+#![feature(macro_rules, phase, globs, thread_local, asm)]
 #![feature(linkage, lang_items, unsafe_destructor, default_type_params)]
 #![feature(import_shadowing, slicing_syntax)]
 #![no_std]
diff --git a/src/libserialize/lib.rs b/src/libserialize/lib.rs
index 8c2f3235322..6de8ca19844 100644
--- a/src/libserialize/lib.rs
+++ b/src/libserialize/lib.rs
@@ -24,7 +24,7 @@ Core encoding and decoding interfaces.
        html_root_url = "http://doc.rust-lang.org/master/",
        html_playground_url = "http://play.rust-lang.org/")]
 #![allow(unknown_features)]
-#![feature(macro_rules, managed_boxes, default_type_params, phase, slicing_syntax)]
+#![feature(macro_rules, default_type_params, phase, slicing_syntax)]
 
 // test harness access
 #[cfg(test)]
diff --git a/src/libstd/lib.rs b/src/libstd/lib.rs
index f6c37b6cfc3..19b4d430562 100644
--- a/src/libstd/lib.rs
+++ b/src/libstd/lib.rs
@@ -106,7 +106,7 @@
        html_playground_url = "http://play.rust-lang.org/")]
 
 #![allow(unknown_features)]
-#![feature(macro_rules, globs, managed_boxes, linkage)]
+#![feature(macro_rules, globs, linkage)]
 #![feature(default_type_params, phase, lang_items, unsafe_destructor)]
 #![feature(import_shadowing, slicing_syntax)]
 
diff --git a/src/libsyntax/feature_gate.rs b/src/libsyntax/feature_gate.rs
index 8565bebe269..7dcc039a83f 100644
--- a/src/libsyntax/feature_gate.rs
+++ b/src/libsyntax/feature_gate.rs
@@ -40,7 +40,7 @@ static KNOWN_FEATURES: &'static [(&'static str, Status)] = &[
     ("struct_variant", Active),
     ("once_fns", Active),
     ("asm", Active),
-    ("managed_boxes", Active),
+    ("managed_boxes", Removed),
     ("non_ascii_idents", Active),
     ("thread_local", Active),
     ("link_args", Active),
diff --git a/src/test/auxiliary/issue_16723_multiple_items_syntax_ext.rs b/src/test/auxiliary/issue_16723_multiple_items_syntax_ext.rs
index ee5bc55b3fd..bb57b4a98bb 100644
--- a/src/test/auxiliary/issue_16723_multiple_items_syntax_ext.rs
+++ b/src/test/auxiliary/issue_16723_multiple_items_syntax_ext.rs
@@ -11,7 +11,7 @@
 // ignore-stage1
 // force-host
 
-#![feature(plugin_registrar, managed_boxes, quote)]
+#![feature(plugin_registrar, quote)]
 #![crate_type = "dylib"]
 
 extern crate syntax;