Yes, it’s coming! Can you handle it? I can! (My bookshelf can’t, but that’s a different story.)
It was announced on Kate Cary’s blog that HarperCollins (and thousands of fans) have requested a fifth series of Warriors. Stay tuned for more updates (which probably aren’t coming anytime soon).
-Seedfur
Forest Felines Warrior Cat Updates and More 
Robinwing Said:
on August 13, 2010 at 10:36 am
Wow, that’s great. ^^ I just adore Warriors. I hope they have good plot for the series, but maybe not one that stretches out as far as the last two series, even though the plot was good and the prophecy was kinda forgotten amidst all the secrets and such.
Bluestar Said:
on August 15, 2010 at 12:51 pm
We have to have a 5th series! I don’t want it to end! THEN what would I read in class when I am bored??