diff --git a/src/libnative/io/process.rs b/src/libnative/io/process.rs
index 21da0104c2f8d70eb2539791fde4d2b22a7c681a..e3e6ae425266e586265c3e2866390bd8c83c4420 100644
--- a/src/libnative/io/process.rs
+++ b/src/libnative/io/process.rs
@@ -305,6 +305,25 @@ fn spawn_process_os(cfg: ProcessConfig,
         })
     }
 
+    // To have the spawning semantics of unix/windows stay the same, we need to
+    // read the *child's* PATH if one is provided. See #15149 for more details.
+    let program = cfg.env.and_then(|env| {
+        for &(ref key, ref v) in env.iter() {
+            if b"PATH" != key.as_bytes_no_nul() { continue }
+
+            // Split the value and test each path to see if the program exists.
+            for path in os::split_paths(v.as_bytes_no_nul()).move_iter() {
+                let path = path.join(cfg.program.as_bytes_no_nul())
+                               .with_extension(os::consts::EXE_EXTENSION);
+                if path.exists() {
+                    return Some(path.to_c_str())
+                }
+            }
+            break
+        }
+        None
+    });
+
     unsafe {
         let mut si = zeroed_startupinfo();
         si.cb = mem::size_of::<STARTUPINFO>() as DWORD;
@@ -362,7 +381,8 @@ fn spawn_process_os(cfg: ProcessConfig,
         try!(set_fd(&out_fd, &mut si.hStdOutput, false));
         try!(set_fd(&err_fd, &mut si.hStdError, false));
 
-        let cmd_str = make_command_line(cfg.program, cfg.args);
+        let cmd_str = make_command_line(program.as_ref().unwrap_or(cfg.program),
+                                        cfg.args);
         let mut pi = zeroed_process_information();
         let mut create_err = None;
 
diff --git a/src/test/run-pass/issue-15149.rs b/src/test/run-pass/issue-15149.rs
new file mode 100644
index 0000000000000000000000000000000000000000..d76a7109ced8e7d87a192cc263432a7cede1116f
--- /dev/null
+++ b/src/test/run-pass/issue-15149.rs
@@ -0,0 +1,56 @@
+// Copyright 2014 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.
+
+#![feature(phase)]
+extern crate native;
+#[phase(plugin)]
+extern crate green;
+
+use native::NativeTaskBuilder;
+use std::io::{TempDir, Command, fs};
+use std::os;
+use std::task::TaskBuilder;
+
+// FIXME(#15149) libgreen still needs to be update. There is an open PR for it
+//               but it is not yet merged.
+// green_start!(main)
+
+fn main() {
+    // If we're the child, make sure we were invoked correctly
+    let args = os::args();
+    if args.len() > 1 && args.get(1).as_slice() == "child" {
+        return assert_eq!(args.get(0).as_slice(), "mytest");
+    }
+
+    test();
+    let (tx, rx) = channel();
+    TaskBuilder::new().native().spawn(proc() {
+        tx.send(test());
+    });
+    rx.recv();
+}
+
+fn test() {
+    // If we're the parent, copy our own binary to a tempr directory, and then
+    // make it executable.
+    let dir = TempDir::new("mytest").unwrap();
+    let me = os::self_exe_name().unwrap();
+    let dest = dir.path().join(format!("mytest{}", os::consts::EXE_SUFFIX));
+    fs::copy(&me, &dest).unwrap();
+
+    // Append the temp directory to our own PATH.
+    let mut path = os::split_paths(os::getenv("PATH").unwrap_or(String::new()));
+    path.push(dir.path().clone());
+    let path = os::join_paths(path.as_slice()).unwrap();
+
+    Command::new("mytest").env("PATH", path.as_slice())
+                          .arg("child")
+                          .spawn().unwrap();
+}