diff --git a/ircevent/irc.go b/ircevent/irc.go
index 6bcc6a4..81de533 100644
--- a/ircevent/irc.go
+++ b/ircevent/irc.go
@@ -336,10 +336,15 @@ func (irc *Connection) sendInternal(b []byte) (err error) {
 	// `end` is closed), but invocations from outside do (even though the race window
 	// is very small).
 	irc.stateMutex.Lock()
+	running := irc.running
 	end := irc.end
 	pwrite := irc.pwrite
 	irc.stateMutex.Unlock()
 
+	if !running {
+		return ClientDisconnected
+	}
+
 	select {
 	case pwrite <- b:
 		return nil