diff --git a/errbot/backends/irc.py b/errbot/backends/irc.py
index ca09e4950..b033903ba 100644
--- a/errbot/backends/irc.py
+++ b/errbot/backends/irc.py
@@ -52,7 +52,13 @@
                           end_inline_code='')
 
 IRC_NICK_REGEX = r'[a-zA-Z\[\]\\`_\^\{\|\}][a-zA-Z0-9\[\]\\`_\^\{\|\}-]+'
-IRC_MESSAGE_SIZE_LIMIT = 510
+# According to the RFC the IRC message size can be at most 512 bytes
+# Out of these 2 bytes are necessary for '\r\n'.
+# At least 10 bytes for 'PRIVMSG <to> :'
+# (note that <to> is being taken care of in split_and_send_message
+#  using MESSAGE_SIZE_LIMIT_INCLUDES_ADDRESEE)
+# And one more byte for b'\x03' -- EXT - End Of Text
+IRC_MESSAGE_SIZE_LIMIT = 499
 
 try:
     import irc.connection
@@ -669,6 +675,7 @@ def __init__(self, config):
                                   )
         self.md = irc_md()
         config.MESSAGE_SIZE_LIMIT = IRC_MESSAGE_SIZE_LIMIT
+        config.MESSAGE_SIZE_LIMIT_INCLUDES_ADDRESEE = True
 
     def send_message(self, msg):
         super().send_message(msg)
diff --git a/errbot/bootstrap.py b/errbot/bootstrap.py
index 5b9634c46..c087d5086 100644
--- a/errbot/bootstrap.py
+++ b/errbot/bootstrap.py
@@ -42,7 +42,10 @@ def bot_config_defaults(config):
     if not hasattr(config, 'DIVERT_TO_PRIVATE'):
         config.DIVERT_TO_PRIVATE = ()
     if not hasattr(config, 'MESSAGE_SIZE_LIMIT'):
-        config.MESSAGE_SIZE_LIMIT = 10000  # Corresponds with what HipChat accepts
+        # Corresponds with what HipChat accepts
+        config.MESSAGE_SIZE_LIMIT = 10000
+    if not hasattr(config, 'MESSAGE_SIZE_LIMIT_INCLUDES_ADDRESEE'):
+        config.MESSAGE_SIZE_LIMIT_INCLUDES_ADDRESEE = False
     if not hasattr(config, 'GROUPCHAT_NICK_PREFIXED'):
         config.GROUPCHAT_NICK_PREFIXED = False
     if not hasattr(config, 'AUTOINSTALL_DEPS'):
diff --git a/errbot/core.py b/errbot/core.py
index bbcbba078..14507854b 100644
--- a/errbot/core.py
+++ b/errbot/core.py
@@ -158,7 +158,14 @@ def send_templated(self, identifier, template_name, template_parameters, in_repl
         return self.send(identifier, text, in_reply_to, groupchat_nick_reply)
 
     def split_and_send_message(self, msg):
-        for part in split_string_after(msg.body, self.bot_config.MESSAGE_SIZE_LIMIT):
+        size_limit = self.bot_config.MESSAGE_SIZE_LIMIT
+
+        # If MESSAGE_SIZE_LIMIT_INCLUDES_ADDRESEE is set to True, lower the
+        # size_limit by the size of the string representation of the addressee
+        if self.bot_config.MESSAGE_SIZE_LIMIT_INCLUDES_ADDRESEE:
+            size_limit -= len(str(msg.to))
+
+        for part in split_string_after(msg.body, size_limit):
             partial_message = msg.clone()
             partial_message.body = part
             self.send_message(partial_message)