diff --git a/src/pkg/os/exec.go b/src/pkg/os/exec.go
index 33e223fd29..6e0f168c76 100644
--- a/src/pkg/os/exec.go
+++ b/src/pkg/os/exec.go
@@ -12,11 +12,11 @@ import (
 // Process stores the information about a process created by StartProcess.
 type Process struct {
 	Pid    int
-	handle int
+	handle uintptr
 	done   bool // process has been successfuly waited on
 }
 
-func newProcess(pid, handle int) *Process {
+func newProcess(pid int, handle uintptr) *Process {
 	p := &Process{Pid: pid, handle: handle}
 	runtime.SetFinalizer(p, (*Process).Release)
 	return p
diff --git a/src/pkg/os/exec_windows.go b/src/pkg/os/exec_windows.go
index c7e25f9853..b89f91c197 100644
--- a/src/pkg/os/exec_windows.go
+++ b/src/pkg/os/exec_windows.go
@@ -46,14 +46,14 @@ func (p *Process) Signal(sig Signal) error {
 
 // Release releases any resources associated with the Process.
 func (p *Process) Release() error {
-	if p.handle == -1 {
+	if p.handle == uintptr(syscall.InvalidHandle) {
 		return EINVAL
 	}
 	e := syscall.CloseHandle(syscall.Handle(p.handle))
 	if e != nil {
 		return NewSyscallError("CloseHandle", e)
 	}
-	p.handle = -1
+	p.handle = uintptr(syscall.InvalidHandle)
 	// no need for a finalizer anymore
 	runtime.SetFinalizer(p, nil)
 	return nil
@@ -66,7 +66,7 @@ func findProcess(pid int) (p *Process, err error) {
 	if e != nil {
 		return nil, NewSyscallError("OpenProcess", e)
 	}
-	return newProcess(pid, int(h)), nil
+	return newProcess(pid, uintptr(h)), nil
 }
 
 func init() {
diff --git a/src/pkg/syscall/exec_plan9.go b/src/pkg/syscall/exec_plan9.go
index 788666b2f2..de6421c239 100644
--- a/src/pkg/syscall/exec_plan9.go
+++ b/src/pkg/syscall/exec_plan9.go
@@ -483,7 +483,7 @@ func ForkExec(argv0 string, argv []string, attr *ProcAttr) (pid int, err error)
 }
 
 // StartProcess wraps ForkExec for package os.
-func StartProcess(argv0 string, argv []string, attr *ProcAttr) (pid, handle int, err error) {
+func StartProcess(argv0 string, argv []string, attr *ProcAttr) (pid int, handle uintptr, err error) {
 	pid, err = forkExec(argv0, argv, attr)
 	return pid, 0, err
 }
diff --git a/src/pkg/syscall/exec_unix.go b/src/pkg/syscall/exec_unix.go
index ad3cf48c80..b70e1880b9 100644
--- a/src/pkg/syscall/exec_unix.go
+++ b/src/pkg/syscall/exec_unix.go
@@ -208,7 +208,7 @@ func ForkExec(argv0 string, argv []string, attr *ProcAttr) (pid int, err error)
 }
 
 // StartProcess wraps ForkExec for package os.
-func StartProcess(argv0 string, argv []string, attr *ProcAttr) (pid, handle int, err error) {
+func StartProcess(argv0 string, argv []string, attr *ProcAttr) (pid int, handle uintptr, err error) {
 	pid, err = forkExec(argv0, argv, attr)
 	return pid, 0, err
 }
diff --git a/src/pkg/syscall/exec_windows.go b/src/pkg/syscall/exec_windows.go
index 2826e2f35a..6cb25a7d00 100644
--- a/src/pkg/syscall/exec_windows.go
+++ b/src/pkg/syscall/exec_windows.go
@@ -232,7 +232,7 @@ type SysProcAttr struct {
 var zeroProcAttr ProcAttr
 var zeroSysProcAttr SysProcAttr
 
-func StartProcess(argv0 string, argv []string, attr *ProcAttr) (pid, handle int, err error) {
+func StartProcess(argv0 string, argv []string, attr *ProcAttr) (pid int, handle uintptr, err error) {
 	if len(argv0) == 0 {
 		return 0, 0, EWINDOWS
 	}
@@ -319,7 +319,7 @@ func StartProcess(argv0 string, argv []string, attr *ProcAttr) (pid, handle int,
 	}
 	defer CloseHandle(Handle(pi.Thread))
 
-	return int(pi.ProcessId), int(pi.Process), nil
+	return int(pi.ProcessId), uintptr(pi.Process), nil
 }
 
 func Exec(argv0 string, argv []string, envv []string) (err error) {