diff --git a/process_darwin.go b/process_darwin.go
index 5f6ad16..5e1299f 100644
--- a/process_darwin.go
+++ b/process_darwin.go
@@ -71,9 +71,6 @@ func (p *Process) Status() (string, error) {
 
 	return string(k.KiStat[:]), nil
 }
-func (p *Process) Username() (string, error) {
-	return "", NotImplementedError
-}
 func (p *Process) Uids() ([]int32, error) {
 	k, err := p.getKProc()
 	if err != nil {
diff --git a/process_freebsd.go b/process_freebsd.go
index ee33a69..101b3fc 100644
--- a/process_freebsd.go
+++ b/process_freebsd.go
@@ -69,9 +69,6 @@ func (p *Process) Status() (string, error) {
 
 	return string(k.KiStat[:]), nil
 }
-func (p *Process) Username() (string, error) {
-	return "", NotImplementedError
-}
 func (p *Process) Uids() ([]int32, error) {
 	k, err := p.getKProc()
 	if err != nil {
diff --git a/process_linux.go b/process_linux.go
index a24a8e4..982e2ae 100644
--- a/process_linux.go
+++ b/process_linux.go
@@ -101,9 +101,6 @@ func (p *Process) Status() (string, error) {
 	}
 	return status, nil
 }
-func (p *Process) Username() (string, error) {
-	return "", nil
-}
 func (p *Process) Uids() ([]int32, error) {
 	_, _, uids, _, _, _, err := p.fillFromStatus()
 	if err != nil {
diff --git a/process_posix.go b/process_posix.go
index 03bd5d8..1514dc7 100644
--- a/process_posix.go
+++ b/process_posix.go
@@ -4,6 +4,7 @@ package gopsutil
 
 import (
 	"os"
+	"os/user"
 	"os/exec"
 	"strconv"
 	"strings"
@@ -85,3 +86,17 @@ func (p *Process) Terminate() error {
 func (p *Process) Kill() error {
 	return p.SendSignal(syscall.SIGKILL)
 }
+func (p *Process) Username() (string, error) {
+	uids, err := p.Uids()
+	if err != nil {
+		return "", err
+	}
+	if len(uids) > 0 {
+		u, err := user.LookupId(strconv.Itoa(int(uids[0])))
+		if err != nil {
+			return "", err
+		}
+		return u.Username, nil
+	}
+	return "", nil
+}