diff --git a/main.go b/main.go
index d12b68d..8a7c77a 100644
--- a/main.go
+++ b/main.go
@@ -31,6 +31,7 @@ type Client struct {
 	conn             net.Conn
 	host             string
 	channels         map[string]*Channel
+	monitorTargets   map[string]bool
 	registered       bool
 	saslRequired     bool
 	saslComplete     bool
@@ -153,10 +154,11 @@ func handleConn(conn net.Conn) {
 
 	reader := bufio.NewReader(conn)
 	client := &Client{
-		conn:       conn,
-		host:       host,
-		channels:   make(map[string]*Channel),
-		registered: false,
+		conn:           conn,
+		host:           host,
+		channels:       make(map[string]*Channel),
+		monitorTargets: make(map[string]bool),
+		registered:     false,
 	}
 	defer client.cleanup()
 	for {
@@ -186,6 +188,10 @@ func handleConn(conn net.Conn) {
 					}
 					clients[newNick] = client
 					cliMu.Unlock()
+					if oldNick != "" {
+						notifyMonitorsOffline(oldNick)
+					}
+					notifyMonitorsOnline(newNick)
 					for _, ch := range client.channels {
 						ch.mu.Lock()
 						if oldNick != "" {
@@ -461,6 +467,22 @@ func handleConn(conn net.Conn) {
 			} else {
 				fmt.Fprintf(client.conn, ":server 461 %s NAMES :Not enough parameters\r\n", client.nick)
 			}
+		case "ISON":
+			if len(msg.Params) < 1 {
+				client.fwrite(":server 461 %s ISON :Not enough parameters\r\n", client.nick)
+				continue
+			}
+			requested := msg.Params
+			var online []string
+
+			cliMu.RLock()
+			for _, nick := range requested {
+				if _, ok := clients[nick]; ok {
+					online = append(online, nick)
+				}
+			}
+			cliMu.RUnlock()
+			client.fwrite(":server 303 %s :%s\r\n", client.nick, strings.Join(online, " "))
 			// ircv3 stuff
 		case "CHATHISTORY":
 			if len(msg.Params) < 4 {
@@ -475,6 +497,38 @@ func handleConn(conn net.Conn) {
 				continue
 			}
 			client.serveHistory(subcmd, target, count, msg.Params)
+		case "MONITOR":
+			if len(msg.Params) < 1 {
+				client.fwrite(":server 461 %s MONITOR :Not enough parameters\r\n", client.nick)
+				continue
+			}
+			subcmd := strings.ToUpper(msg.Params[0])
+			switch subcmd {
+			case "+":
+				for _, nick := range msg.Params[1:] {
+					client.monitorTargets[nick] = true
+					cliMu.RLock()
+					if _, ok := clients[nick]; ok {
+						client.fwrite(":server 730 %s %s :is online\r\n", client.nick, nick)
+					}
+					cliMu.RUnlock()
+				}
+			case "-":
+				for _, nick := range msg.Params[1:] {
+					delete(client.monitorTargets, nick)
+				}
+			case "C":
+				client.monitorTargets = make(map[string]bool)
+			case "L":
+				var nicks []string
+				for nick := range client.monitorTargets {
+					nicks = append(nicks, nick)
+				}
+				client.fwrite(":server 732 %s :%s\r\n", client.nick, strings.Join(nicks, " "))
+				client.fwrite(":server 733 %s :End of MONITOR list\r\n", client.nick)
+			default:
+				client.fwrite(":server 461 %s MONITOR :Invalid subcommand\r\n", client.nick)
+			}
 		default:
 			if client.nick != "" {
 				fmt.Fprintf(conn, ":server 421 %s %s :Unknown command or command is not implemented\r\n", client.nick, msg.Command)
@@ -884,6 +938,7 @@ func (c *Client) checkRegistration() {
 			return
 		}
 		c.registered = true
+		notifyMonitorsOnline(c.nick)
 		c.fwrite(":server 001 %s :Welcome to Gocirc, %s!\r\n", c.nick, c.nick)
 		c.fwrite(":server 002 %s :Your host is server\r\n", c.nick)
 		c.fwrite(":server 003 %s :This server has %d users right now\r\n", c.nick, len(clients))
@@ -1010,6 +1065,7 @@ func (c *Client) cleanup() {
 	cliMu.Lock()
 	delete(clients, c.nick)
 	cliMu.Unlock()
+	notifyMonitorsOffline(c.nick)
 	for name, ch := range c.channels {
 		ch.mu.Lock()
 		delete(ch.members, c.nick)
@@ -1139,3 +1195,24 @@ func scanRows(rows *sql.Rows, channel string) []HistoryMessage {
 	}
 	return msgs
 }
+
+// IRC MONITOR command stuff
+func notifyMonitorsOnline(nick string) {
+	cliMu.RLock()
+	defer cliMu.RUnlock()
+	for _, c := range clients {
+		if c.monitorTargets[nick] {
+			c.fwrite(":server 730 %s %s :is online\r\n", c.nick, nick)
+		}
+	}
+}
+
+func notifyMonitorsOffline(nick string) {
+	cliMu.RLock()
+	defer cliMu.RUnlock()
+	for _, c := range clients {
+		if c.monitorTargets[nick] {
+			c.fwrite(":server 731 %s %s :is offline\r\n", c.nick, nick)
+		}
+	}
+}