diff --git a/netpoll/netpoll_epoll.go b/netpoll/netpoll_epoll.go
index 7f8a3b0..a548ad2 100644
--- a/netpoll/netpoll_epoll.go
+++ b/netpoll/netpoll_epoll.go
@@ -23,7 +23,7 @@ type poller struct {
 
 // Start implements Poller.Start() method.
 func (ep poller) Start(desc *Desc, cb CallbackFn) error {
-	return ep.Add(desc.fd(), toEpollEvent(desc.event),
+	err := ep.Add(desc.fd(), toEpollEvent(desc.event),
 		func(ep EpollEvent) {
 			var event Event
 
@@ -49,6 +49,8 @@ func (ep poller) Start(desc *Desc, cb CallbackFn) error {
 			cb(event)
 		},
 	)
+	setNonblock(desc.fd(), true)
+	return err
 }
 
 // Stop implements Poller.Stop() method.
diff --git a/netpoll/netpoll_kqueue.go b/netpoll/netpoll_kqueue.go
index d604eb0..c4b0fd1 100644
--- a/netpoll/netpoll_kqueue.go
+++ b/netpoll/netpoll_kqueue.go
@@ -22,7 +22,7 @@ type poller struct {
 
 func (p poller) Start(desc *Desc, cb CallbackFn) error {
 	n, events := toKevents(desc.event, true)
-	return p.Add(desc.fd(), events, n, func(kev Kevent) {
+	err := p.Add(desc.fd(), events, n, func(kev Kevent) {
 		var (
 			event Event
 
@@ -57,6 +57,8 @@ func (p poller) Start(desc *Desc, cb CallbackFn) error {
 
 		cb(event)
 	})
+	setNonblock(desc.fd(), true)
+	return err
 }
 
 func (p poller) Stop(desc *Desc) error {