diff --git a/src/cmd/gofix/Makefile b/src/cmd/gofix/Makefile
index 020a6a2..9383f5a 100644
--- a/src/cmd/gofix/Makefile
+++ b/src/cmd/gofix/Makefile
@@ -9,6 +9,7 @@
 	fix.go\
 	main.go\
 	httpserver.go\
+	procattr.go\
 
 include ../../Make.cmd
 
diff --git a/src/cmd/gofix/fix.go b/src/cmd/gofix/fix.go
index eadddba..69af991 100644
--- a/src/cmd/gofix/fix.go
+++ b/src/cmd/gofix/fix.go
@@ -264,6 +264,11 @@
 	return id.String() == name
 }
 
+func isCall(t ast.Expr, pkg, name string) bool {
+	call, ok := t.(*ast.CallExpr)
+	return ok && isPkgDot(call.Fun, pkg, name)
+}
+
 func refersTo(n ast.Node, x *ast.Ident) bool {
 	id, ok := n.(*ast.Ident)
 	if !ok {
diff --git a/src/cmd/gofix/httpserver_test.go b/src/cmd/gofix/httpserver_test.go
index 7e79056..eca2a76 100644
--- a/src/cmd/gofix/httpserver_test.go
+++ b/src/cmd/gofix/httpserver_test.go
@@ -1,3 +1,7 @@
+// Copyright 2011 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.
+
 package main
 
 func init() {
diff --git a/src/cmd/gofix/main.go b/src/cmd/gofix/main.go
index 40c86e8..9ca2ddb 100644
--- a/src/cmd/gofix/main.go
+++ b/src/cmd/gofix/main.go
@@ -82,7 +82,7 @@
 const (
 	tabWidth    = 8
 	parserMode  = parser.ParseComments
-	printerMode = printer.TabIndent
+	printerMode = printer.TabIndent | printer.UseSpaces
 )
 
 
diff --git a/src/cmd/gofix/main_test.go b/src/cmd/gofix/main_test.go
index 597bff2..e4d0f60 100644
--- a/src/cmd/gofix/main_test.go
+++ b/src/cmd/gofix/main_test.go
@@ -6,9 +6,12 @@
 
 import (
 	"bytes"
+	"exec"
 	"go/ast"
 	"go/parser"
 	"go/printer"
+	"io/ioutil"
+	"os"
 	"testing"
 )
 
@@ -42,6 +45,7 @@
 	if s := buf.String(); in != s {
 		t.Errorf("%s: not gofmt-formatted.\n--- %s\n%s\n--- %s | gofmt\n%s",
 			desc, desc, in, desc, s)
+		tdiff(t, in, s)
 		return
 	}
 
@@ -75,6 +79,7 @@
 
 		if out != tt.Out {
 			t.Errorf("%s: incorrect output.\n--- have\n%s\n--- want\n%s", tt.Name, out, tt.Out)
+			tdiff(t, out, tt.Out)
 			continue
 		}
 
@@ -97,6 +102,50 @@
 		if out2 != out {
 			t.Errorf("%s: changed output after second round of fixes.\n--- output after first round\n%s\n--- output after second round\n%s",
 				tt.Name, out, out2)
+			tdiff(t, out, out2)
 		}
 	}
 }
+
+func tdiff(t *testing.T, a, b string) {
+	f1, err := ioutil.TempFile("", "gofix")
+	if err != nil {
+		t.Error(err)
+		return
+	}
+	defer os.Remove(f1.Name())
+	defer f1.Close()
+
+	f2, err := ioutil.TempFile("", "gofix")
+	if err != nil {
+		t.Error(err)
+		return
+	}
+	defer os.Remove(f2.Name())
+	defer f2.Close()
+
+	f1.Write([]byte(a))
+	f2.Write([]byte(b))
+
+	diffcmd, err := exec.LookPath("diff")
+	if err != nil {
+		t.Error(err)
+		return
+	}
+
+	c, err := exec.Run(diffcmd, []string{"diff", f1.Name(), f2.Name()}, nil, "",
+		exec.DevNull, exec.Pipe, exec.MergeWithStdout)
+	if err != nil {
+		t.Error(err)
+		return
+	}
+	defer c.Close()
+
+	data, err := ioutil.ReadAll(c.Stdout)
+	if err != nil {
+		t.Error(err)
+		return
+	}
+
+	t.Error(string(data))
+}
diff --git a/src/cmd/gofix/procattr.go b/src/cmd/gofix/procattr.go
new file mode 100644
index 0000000..3409776
--- /dev/null
+++ b/src/cmd/gofix/procattr.go
@@ -0,0 +1,61 @@
+// Copyright 2011 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.
+
+package main
+
+import (
+	"go/ast"
+	"go/token"
+)
+
+var procattrFix = fix{
+	"procattr",
+	procattr,
+`Adapt calls to os.StartProcess to use new ProcAttr type.
+
+http://codereview.appspot.com/4253052
+`,
+}
+
+func init() {
+	register(httpserverFix)
+}
+
+func procattr(f *ast.File) bool {
+	if !imports(f, "os") && !imports(f, "syscall") {
+		return false
+	}
+
+	fixed := false
+	rewrite(f, func(n interface{}) {
+		call, ok := n.(*ast.CallExpr)
+		if !ok || len(call.Args) != 5 {
+			return
+		}
+		var pkg string
+		if isPkgDot(call.Fun, "os", "StartProcess") {
+			pkg = "os"
+		} else if isPkgDot(call.Fun, "syscall", "StartProcess") {
+			pkg = "syscall"
+		} else {
+			return
+		}
+		// os.StartProcess(a, b, c, d, e) -> os.StartProcess(a, b, &os.ProcAttr{Env: c, Dir: d, Files: e})
+		lit := &ast.CompositeLit{Type: ast.NewIdent(pkg + ".ProcAttr")}
+		env, dir, files := call.Args[2], call.Args[3], call.Args[4]
+		if !isName(env, "nil") && !isCall(env, "os", "Environ") {
+			lit.Elts = append(lit.Elts, &ast.KeyValueExpr{Key: ast.NewIdent("Env"), Value: env})
+		}
+		if !isEmptyString(dir) {
+			lit.Elts = append(lit.Elts, &ast.KeyValueExpr{Key: ast.NewIdent("Dir"), Value: dir})
+		}
+		if !isName(files, "nil") {
+			lit.Elts = append(lit.Elts, &ast.KeyValueExpr{Key: ast.NewIdent("Files"), Value: files})
+		}
+		call.Args[2] = &ast.UnaryExpr{Op: token.AND, X: lit}
+		call.Args = call.Args[:3]
+		fixed = true
+	})
+	return fixed
+}
diff --git a/src/cmd/gofix/procattr_test.go b/src/cmd/gofix/procattr_test.go
new file mode 100644
index 0000000..1a8eb86
--- /dev/null
+++ b/src/cmd/gofix/procattr_test.go
@@ -0,0 +1,75 @@
+// Copyright 2011 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.
+
+package main
+
+func init() {
+	addTestCases(procattrTests)
+}
+
+var procattrTests = []testCase{
+	{
+		Name: "procattr.0",
+		Fn:   procattr,
+		In: `package main
+
+import (
+	"os"
+	"syscall"
+)
+
+func f() {
+	os.StartProcess(a, b, c, d, e)
+	os.StartProcess(a, b, os.Environ(), d, e)
+	os.StartProcess(a, b, nil, d, e)
+	os.StartProcess(a, b, c, "", e)
+	os.StartProcess(a, b, c, d, nil)
+	os.StartProcess(a, b, nil, "", nil)
+
+	os.StartProcess(
+		a,
+		b,
+		c,
+		d,
+		e,
+	)
+
+	syscall.StartProcess(a, b, c, d, e)
+	syscall.StartProcess(a, b, os.Environ(), d, e)
+	syscall.StartProcess(a, b, nil, d, e)
+	syscall.StartProcess(a, b, c, "", e)
+	syscall.StartProcess(a, b, c, d, nil)
+	syscall.StartProcess(a, b, nil, "", nil)
+}
+`,
+		Out: `package main
+
+import (
+	"os"
+	"syscall"
+)
+
+func f() {
+	os.StartProcess(a, b, &os.ProcAttr{Env: c, Dir: d, Files: e})
+	os.StartProcess(a, b, &os.ProcAttr{Dir: d, Files: e})
+	os.StartProcess(a, b, &os.ProcAttr{Dir: d, Files: e})
+	os.StartProcess(a, b, &os.ProcAttr{Env: c, Files: e})
+	os.StartProcess(a, b, &os.ProcAttr{Env: c, Dir: d})
+	os.StartProcess(a, b, &os.ProcAttr{})
+
+	os.StartProcess(
+		a,
+		b, &os.ProcAttr{Env: c, Dir: d, Files: e},
+	)
+
+	syscall.StartProcess(a, b, &syscall.ProcAttr{Env: c, Dir: d, Files: e})
+	syscall.StartProcess(a, b, &syscall.ProcAttr{Dir: d, Files: e})
+	syscall.StartProcess(a, b, &syscall.ProcAttr{Dir: d, Files: e})
+	syscall.StartProcess(a, b, &syscall.ProcAttr{Env: c, Files: e})
+	syscall.StartProcess(a, b, &syscall.ProcAttr{Env: c, Dir: d})
+	syscall.StartProcess(a, b, &syscall.ProcAttr{})
+}
+`,
+	},
+}