diff --git a/irc/conn.go b/irc/conn.go
index 2f09420f..5bab21ab 100644
--- a/irc/conn.go
+++ b/irc/conn.go
@@ -189,7 +189,7 @@ func (c *Client) recv() {
 		case ReplyWelcome:
 			c.once.Do(c.ready.Done)
 
-		case "433":
+		case ErrNicknameInUse:
 			if c.HandleNickInUse != nil {
 				c.nick = c.HandleNickInUse(c.nick)
 				c.writeNick(c.nick)
diff --git a/irc/const.go b/irc/const.go
index d2c053e3..87fd6a7b 100644
--- a/irc/const.go
+++ b/irc/const.go
@@ -32,4 +32,5 @@ const (
 	ReplyMotd          = "372"
 	ReplyMotdStart     = "375"
 	ReplyEndOfMotd     = "376"
+	ErrNicknameInUse   = "433"
 )