diff --git a/src/pkg/io/ioutil/tempfile.go b/src/pkg/io/ioutil/tempfile.go
index 55fcf47026d..114eca2b50e 100644
--- a/src/pkg/io/ioutil/tempfile.go
+++ b/src/pkg/io/ioutil/tempfile.go
@@ -33,18 +33,15 @@ func nextSuffix() string {
 // TempFile creates a new temporary file in the directory dir
 // with a name beginning with prefix, opens the file for reading
 // and writing, and returns the resulting *os.File.
-// If dir is the empty string, TempFile uses the value of the
-// environment variable $TMPDIR or, if that is empty,/tmp.
+// If dir is the empty string, TempFile uses the default directory
+// for temporary files (see os.TempDir).
 // Multiple programs calling TempFile simultaneously
 // will not choose the same file.  The caller can use f.Name()
 // to find the name of the file.  It is the caller's responsibility to
 // remove the file when no longer needed.
 func TempFile(dir, prefix string) (f *os.File, err os.Error) {
 	if dir == "" {
-		dir = os.Getenv("TMPDIR")
-		if dir == "" {
-			dir = "/tmp"
-		}
+		dir = os.TempDir()
 	}
 
 	nconflict := 0
diff --git a/src/pkg/io/ioutil/tempfile_test.go b/src/pkg/io/ioutil/tempfile_test.go
index fbe45dc6dd6..fe43f956685 100644
--- a/src/pkg/io/ioutil/tempfile_test.go
+++ b/src/pkg/io/ioutil/tempfile_test.go
@@ -7,6 +7,7 @@ package ioutil_test
 import (
 	. "io/ioutil"
 	"os"
+	"regexp"
 	"testing"
 )
 
@@ -16,14 +17,17 @@ func TestTempFile(t *testing.T) {
 		t.Errorf("TempFile(`/_not_exists_`, `foo`) = %v, %v", f, err)
 	}
 
-	f, err = TempFile("/tmp", "ioutil_test")
+	dir := os.TempDir()
+	f, err = TempFile(dir, "ioutil_test")
 	if f == nil || err != nil {
-		t.Errorf("TempFile(`/tmp`, `ioutil_test`) = %v, %v", f, err)
+		t.Errorf("TempFile(dir, `ioutil_test`) = %v, %v", f, err)
 	}
-	re := testing.MustCompile("^/tmp/ioutil_test[0-9]+$")
-	if !re.MatchString(f.Name()) {
-		t.Fatalf("TempFile(`/tmp`, `ioutil_test`) created bad name %s", f.Name())
+	if f != nil {
+		re := testing.MustCompile("^" + regexp.QuoteMeta(dir) + "/ioutil_test[0-9]+$")
+		if !re.MatchString(f.Name()) {
+			t.Errorf("TempFile(`"+dir+"`, `ioutil_test`) created bad name %s", f.Name())
+		}
+		os.Remove(f.Name())
 	}
-	os.Remove(f.Name())
 	f.Close()
 }
diff --git a/src/pkg/os/Makefile b/src/pkg/os/Makefile
index 71de9495147..45954bbeb81 100644
--- a/src/pkg/os/Makefile
+++ b/src/pkg/os/Makefile
@@ -19,22 +19,27 @@ GOFILES=\
 	types.go\
 
 GOFILES_freebsd=\
+	env_unix.go\
 	file_unix.go\
 	sys_bsd.go\
 
 GOFILES_darwin=\
+	env_unix.go\
 	file_unix.go\
 	sys_bsd.go\
 
 GOFILES_linux=\
+	env_unix.go\
 	file_unix.go\
 	sys_linux.go\
 
 GOFILES_nacl=\
+	env_unix.go\
 	file_unix.go\
 	sys_nacl.go\
 
 GOFILES_windows=\
+	env_windows.go\
 	file_windows.go\
 	sys_windows.go\
 
diff --git a/src/pkg/os/env_unix.go b/src/pkg/os/env_unix.go
new file mode 100755
index 00000000000..0c13bda0e36
--- /dev/null
+++ b/src/pkg/os/env_unix.go
@@ -0,0 +1,19 @@
+// Copyright 2010 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Unix environment variables.
+
+package os
+
+// TempDir returns the default directory to use for temporary files.
+// On Unix-like systems, it uses the environment variable $TMPDIR
+// or, if that is empty, /tmp.
+// On Windows systems, it uses the Windows GetTempPath API.
+func TempDir() string {
+	dir := Getenv("TMPDIR")
+	if dir == "" {
+		dir = "/tmp"
+	}
+	return dir
+}
diff --git a/src/pkg/os/env_windows.go b/src/pkg/os/env_windows.go
new file mode 100755
index 00000000000..7d5b007c930
--- /dev/null
+++ b/src/pkg/os/env_windows.go
@@ -0,0 +1,29 @@
+// Copyright 2010 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Windows environment variables.
+
+package os
+
+import (
+	"syscall"
+	"utf16"
+)
+
+func TempDir() string {
+	const pathSep = '\\'
+	dirw := make([]uint16, syscall.MAX_PATH)
+	n, _ := syscall.GetTempPath(uint32(len(dirw)), &dirw[0])
+	if n > uint32(len(dirw)) {
+		dirw = make([]uint16, n)
+		n, _ = syscall.GetTempPath(uint32(len(dirw)), &dirw[0])
+		if n > uint32(len(dirw)) {
+			n = 0
+		}
+	}
+	if n > 0 && dirw[n-1] == pathSep {
+		n--
+	}
+	return string(utf16.Decode(dirw[0:n]))
+}
diff --git a/src/pkg/syscall/syscall_windows.go b/src/pkg/syscall/syscall_windows.go
index 8b6789221bb..86badb8e939 100644
--- a/src/pkg/syscall/syscall_windows.go
+++ b/src/pkg/syscall/syscall_windows.go
@@ -131,6 +131,7 @@ func getSysProcAddr(m uint32, pname string) uintptr {
 //sys	GetTimeZoneInformation(tzi *Timezoneinformation) (rc uint32, errno int) [failretval=0xffffffff]
 //sys	CreateIoCompletionPort(filehandle int32, cphandle int32, key uint32, threadcnt uint32) (handle int32, errno int)
 //sys	GetQueuedCompletionStatus(cphandle int32, qty *uint32, key *uint32, overlapped **Overlapped, timeout uint32) (ok bool, errno int)
+//sys	GetTempPath(buflen uint32, buf *uint16) (n uint32, errno int) = GetTempPathW
 
 // syscall interface implementation for other packages
 
diff --git a/src/pkg/syscall/zsyscall_windows_386.go b/src/pkg/syscall/zsyscall_windows_386.go
index 306de3031ab..be5dd031c80 100644
--- a/src/pkg/syscall/zsyscall_windows_386.go
+++ b/src/pkg/syscall/zsyscall_windows_386.go
@@ -40,6 +40,7 @@ var (
 	procGetTimeZoneInformation     = getSysProcAddr(modkernel32, "GetTimeZoneInformation")
 	procCreateIoCompletionPort     = getSysProcAddr(modkernel32, "CreateIoCompletionPort")
 	procGetQueuedCompletionStatus  = getSysProcAddr(modkernel32, "GetQueuedCompletionStatus")
+	procGetTempPathW               = getSysProcAddr(modkernel32, "GetTempPathW")
 	procWSAStartup                 = getSysProcAddr(modwsock32, "WSAStartup")
 	procWSACleanup                 = getSysProcAddr(modwsock32, "WSACleanup")
 	procsocket                     = getSysProcAddr(modwsock32, "socket")
@@ -375,6 +376,17 @@ func GetQueuedCompletionStatus(cphandle int32, qty *uint32, key *uint32, overlap
 	return
 }
 
+func GetTempPath(buflen uint32, buf *uint16) (n uint32, errno int) {
+	r0, _, e1 := Syscall(procGetTempPathW, uintptr(buflen), uintptr(unsafe.Pointer(buf)), 0)
+	n = uint32(r0)
+	if n == 0 {
+		errno = int(e1)
+	} else {
+		errno = 0
+	}
+	return
+}
+
 func WSAStartup(verreq uint32, data *WSAData) (sockerrno int) {
 	r0, _, _ := Syscall(procWSAStartup, uintptr(verreq), uintptr(unsafe.Pointer(data)), 0)
 	sockerrno = int(r0)