diff --git a/portlist/netstat_test.go b/portlist/netstat_test.go
index c24f8732e..2b131331e 100644
--- a/portlist/netstat_test.go
+++ b/portlist/netstat_test.go
@@ -53,12 +53,12 @@ udp46      0      0  *.146                 *.*
 
 func TestParsePortsNetstat(t *testing.T) {
 	want := List{
-		Port{"tcp", 23, ""},
-		Port{"tcp", 24, ""},
-		Port{"udp", 104, ""},
-		Port{"udp", 106, ""},
-		Port{"udp", 146, ""},
-		Port{"tcp", 8185, ""}, // but not 8186, 8187, 8188 on localhost
+		Port{"tcp", 23, "", 0},
+		Port{"tcp", 24, "", 0},
+		Port{"udp", 104, "", 0},
+		Port{"udp", 106, "", 0},
+		Port{"udp", 146, "", 0},
+		Port{"tcp", 8185, "", 0}, // but not 8186, 8187, 8188 on localhost
 	}
 
 	pl, err := appendParsePortsNetstat(nil, bufio.NewReader(strings.NewReader(netstatOutput)))
diff --git a/portlist/portlist.go b/portlist/portlist.go
index dd200d191..aa5d11330 100644
--- a/portlist/portlist.go
+++ b/portlist/portlist.go
@@ -18,6 +18,7 @@ type Port struct {
 	Proto   string // "tcp" or "udp"
 	Port    uint16 // port number
 	Process string // optional process name, if found
+	Pid     int    // process id, if known
 }
 
 // List is a list of Ports.
diff --git a/portlist/portlist_macos.go b/portlist/portlist_macos.go
index 13df1c173..0bcb05bd4 100644
--- a/portlist/portlist_macos.go
+++ b/portlist/portlist_macos.go
@@ -11,6 +11,7 @@ import (
 	"fmt"
 	"log"
 	"os/exec"
+	"strconv"
 	"strings"
 	"sync/atomic"
 	"time"
@@ -170,6 +171,7 @@ func (im *macOSImpl) addProcesses() error {
 	im.br.Reset(outPipe)
 
 	var cmd, proto string
+	var pid int
 	for {
 		line, err := im.br.ReadBytes('\n')
 		if err != nil {
@@ -184,6 +186,10 @@ func (im *macOSImpl) addProcesses() error {
 			// starting a new process
 			cmd = ""
 			proto = ""
+			pid = 0
+			if p, err := strconv.Atoi(string(val)); err == nil {
+				pid = p
+			}
 		case 'c':
 			cmd = string(val) // TODO(bradfitz): avoid garbage; cache process names between runs?
 		case 'P':
@@ -202,6 +208,7 @@ func (im *macOSImpl) addProcesses() error {
 			switch {
 			case m != nil:
 				m.port.Process = cmd
+				m.port.Pid = pid
 			default:
 				// ignore: processes and ports come and go
 			}