Yes, according to this article in
Ugo.com article from 2010, "Supernatural and 5 Other Shows That Went On Too Long."
"Given that the current season of Supernatural has the Winchester Boys facing down the Apocalypse, the culmination of every single storyline that's played out through five seasons of the show, it's a little surprising to hear creator Eric Kripke is reportedly "warming" to the idea of a sixth season. This is according to no less than Dawn Ostroff, President of Entertainment at The CW, who revealed this tidbit at the show's 100th Episode Party.
And while it would be nice for Jared Padalecki and Jensen Ackles to have one more year before they slowly fade onto the sci-fi convention autograph circuit, there's really no reason to continue the show beyond the five years that were originally planned."
The rest of the article is
here Strange to read this when the show is heading into Season 10, isn't it? What do you think?
*Note: the site stopped operations in early 2012