diff --git a/CHANGELOG.md b/CHANGELOG.md
index c79cbcf2..5a600d6f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -20,6 +20,7 @@ New release of Oragono!
 
 ### Fixed
 * Fixed bug where `HELP` wouldn't correctly display for operators, and added more help topics.
+* Fixed display of large `MONITOR` lists.
 
 
 ## [0.3.0] - 2016-10-23
diff --git a/irc/constants.go b/irc/constants.go
index fa8af41b..dd0ffe8a 100644
--- a/irc/constants.go
+++ b/irc/constants.go
@@ -15,4 +15,8 @@ const (
 var (
 	// Ver is the full version of Oragono, used in responses to clients.
 	Ver = fmt.Sprintf("oragono-%s", SemVer)
+
+	// maxLastArgLength is used to simply cap off the final argument when creating general messages where we need to select a limit.
+	// for instance, in MONITOR lists, RPL_ISUPPORT lists, etc.
+	maxLastArgLength = 400
 )
diff --git a/irc/isupport.go b/irc/isupport.go
index 9cffb236..6253f1e5 100644
--- a/irc/isupport.go
+++ b/irc/isupport.go
@@ -6,7 +6,6 @@ package irc
 import "fmt"
 
 const isupportSupportedString = "are supported by this server"
-const maxISupportLength = 400 // Max length of a single ISUPPORT token line
 
 // ISupportList holds a list of ISUPPORT tokens
 type ISupportList struct {
@@ -55,7 +54,7 @@ func (il *ISupportList) GetDifference(newil *ISupportList) [][]string {
 
 		token := fmt.Sprintf("-%s", name)
 
-		if len(token)+length <= maxISupportLength {
+		if len(token)+length <= maxLastArgLength {
 			// account for the space separating tokens
 			if len(cache) > 0 {
 				length++
@@ -64,7 +63,7 @@ func (il *ISupportList) GetDifference(newil *ISupportList) [][]string {
 			length += len(token)
 		}
 
-		if len(cache) == 13 || len(token)+length >= maxISupportLength {
+		if len(cache) == 13 || len(token)+length >= maxLastArgLength {
 			cache = append(cache, isupportSupportedString)
 			replies = append(replies, cache)
 			cache = make([]string, 0)
@@ -81,7 +80,7 @@ func (il *ISupportList) GetDifference(newil *ISupportList) [][]string {
 
 		token := getTokenString(name, value)
 
-		if len(token)+length <= maxISupportLength {
+		if len(token)+length <= maxLastArgLength {
 			// account for the space separating tokens
 			if len(cache) > 0 {
 				length++
@@ -90,7 +89,7 @@ func (il *ISupportList) GetDifference(newil *ISupportList) [][]string {
 			length += len(token)
 		}
 
-		if len(cache) == 13 || len(token)+length >= maxISupportLength {
+		if len(cache) == 13 || len(token)+length >= maxLastArgLength {
 			cache = append(cache, isupportSupportedString)
 			replies = append(replies, cache)
 			cache = make([]string, 0)
@@ -115,7 +114,7 @@ func (il *ISupportList) RegenerateCachedReply() {
 	for name, value := range il.Tokens {
 		token := getTokenString(name, value)
 
-		if len(token)+length <= maxISupportLength {
+		if len(token)+length <= maxLastArgLength {
 			// account for the space separating tokens
 			if len(cache) > 0 {
 				length++
@@ -124,7 +123,7 @@ func (il *ISupportList) RegenerateCachedReply() {
 			length += len(token)
 		}
 
-		if len(cache) == 13 || len(token)+length >= maxISupportLength {
+		if len(cache) == 13 || len(token)+length >= maxLastArgLength {
 			cache = append(cache, isupportSupportedString)
 			il.CachedReply = append(il.CachedReply, cache)
 			cache = make([]string, 0)
diff --git a/irc/monitor.go b/irc/monitor.go
index dfa72582..cfe6450e 100644
--- a/irc/monitor.go
+++ b/irc/monitor.go
@@ -116,7 +116,7 @@ func monitorAddHandler(server *Server, client *Client, msg ircmsg.IrcMessage) bo
 	targets := strings.Split(msg.Params[1], ",")
 	for len(targets) > 0 {
 		// check name length
-		if len(targets[0]) < 1 {
+		if len(targets[0]) < 1 || len(targets[0]) > server.limits.NickLen {
 			targets = targets[1:]
 			continue
 		}
@@ -176,7 +176,9 @@ func monitorListHandler(server *Server, client *Client, msg ircmsg.IrcMessage) b
 		monitorList = append(monitorList, name)
 	}
 
-	client.Send(nil, server.name, RPL_MONLIST, client.nick, strings.Join(monitorList, ","))
+	for _, line := range argsToStrings(maxLastArgLength, monitorList, ",") {
+		client.Send(nil, server.name, RPL_MONLIST, client.nick, line)
+	}
 
 	return false
 }
@@ -195,10 +197,14 @@ func monitorStatusHandler(server *Server, client *Client, msg ircmsg.IrcMessage)
 	}
 
 	if len(online) > 0 {
-		client.Send(nil, server.name, RPL_MONONLINE, client.nick, strings.Join(online, ","))
+		for _, line := range argsToStrings(maxLastArgLength, online, ",") {
+			client.Send(nil, server.name, RPL_MONONLINE, client.nick, line)
+		}
 	}
 	if len(offline) > 0 {
-		client.Send(nil, server.name, RPL_MONOFFLINE, client.nick, strings.Join(offline, ","))
+		for _, line := range argsToStrings(maxLastArgLength, offline, ",") {
+			client.Send(nil, server.name, RPL_MONOFFLINE, client.nick, line)
+		}
 	}
 
 	return false
diff --git a/irc/util.go b/irc/util.go
new file mode 100644
index 00000000..03f806c2
--- /dev/null
+++ b/irc/util.go
@@ -0,0 +1,35 @@
+// Copyright (c) 2016- Daniel Oaks <daniel@danieloaks.net>
+// released under the MIT license
+
+package irc
+
+// argsToStrings takes the arguments and splits them into a series of strings,
+// each argument separated by delim and each string bounded by maxLength.
+func argsToStrings(maxLength int, arguments []string, delim string) []string {
+	var messages []string
+
+	var buffer string
+	for {
+		if len(arguments) < 1 {
+			break
+		}
+
+		if len(buffer) > 0 && maxLength < len(buffer)+len(delim)+len(arguments[0]) {
+			messages = append(messages, buffer)
+			buffer = ""
+			continue
+		}
+
+		if len(buffer) > 1 {
+			buffer += delim
+		}
+		buffer += arguments[0]
+		arguments = arguments[1:]
+	}
+
+	if len(buffer) > 0 {
+		messages = append(messages, buffer)
+	}
+
+	return messages
+}