diff --git a/src/librustc/middle/lint.rs b/src/librustc/middle/lint.rs
index 2ba8121b479ea..6711ec4d1cd91 100644
--- a/src/librustc/middle/lint.rs
+++ b/src/librustc/middle/lint.rs
@@ -1127,13 +1127,27 @@ fn check_deprecated_owned_vector(cx: &Context, e: &ast::Expr) {
 
 fn check_item_non_camel_case_types(cx: &Context, it: &ast::Item) {
     fn is_camel_case(ident: ast::Ident) -> bool {
+        // Returns true if char after underscore is invalid.
+        // Accepts trailing underscores to separate types.
+        fn invalid_following_underscore(ident: &str) -> bool {
+            let mut last_was_underscore = false;
+            for c in ident.chars() {
+                if last_was_underscore && !"_0123456789".contains_char(c) {
+                    return true;
+                }
+                last_was_underscore = c == '_';
+            }
+            false
+        }
+
         let ident = token::get_ident(ident);
         assert!(!ident.get().is_empty());
         let ident = ident.get().trim_chars(&'_');
 
         // start with a non-lowercase letter rather than non-uppercase
         // ones (some scripts don't have a concept of upper/lowercase)
-        !ident.char_at(0).is_lowercase() && !ident.contains_char('_')
+        !ident.char_at(0).is_lowercase()
+        && !invalid_following_underscore(ident)
     }
 
     fn check_case(cx: &Context, sort: &str, ident: ast::Ident, span: Span) {
diff --git a/src/test/run-pass/lint-non-camel-case-with-numbers-after-underscore.rs b/src/test/run-pass/lint-non-camel-case-with-numbers-after-underscore.rs
new file mode 100644
index 0000000000000..005da59dbe2fa
--- /dev/null
+++ b/src/test/run-pass/lint-non-camel-case-with-numbers-after-underscore.rs
@@ -0,0 +1,19 @@
+// Copyright 2012 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+// This is ok because we often use underscores to separate numbers
+
+#[forbid(non_camel_case_types)];
+
+type Foo_1_2 = int;
+type _Bar = int;
+type __Baz__1 = int;
+
+pub fn main() { }