KrnACxHunta

To get to the cow level, you have to have at least beaten the game in the difficulty level that you want to go in.

For example, there are three difficuly levels of the cow level just like three difficulty level games. (Normal, Nightmare, Hell) If you want to go to the normal cow level, you had to have already beaten the game in Normal difficulty.

This dates back to Act 1. When you went to Tristram to rescue Deckard Cain, if you went to the very north west of the map, you would have seen a dead man's body whose name is Wart.

If you click on his body, Wart's leg and some money comes out. Pick up Wart's leg.

Put his leg and a teleport scroll in the horadric's cube (you have to be in the Rogue Encampment when you do this). Once you do this, a red portal will appear where the portals usually show up. Go in and there's cows all over the place.

NOTE: if you ever want to come back to the current level of difficulty for the cow level you are in, make sure you do not kill the king cow.

If you kill everything except for the king cow, you can go back to Tristram with some other low level players and get warts leg again and come back again.

But the king cow gives you pretty good items and good exp. so if you want to, go ahead.

Chao Ninja

The Secret Cow Level.
What a wonderful level.
To get to this.
You have to have.
Beaten Ball on the difficulty you are playing on.
Have The Horadric Cube.
Have a Tome of Town Portal (with scrolls in it)
And have Wirt's Leg.
Just go to the Rogue Encampment.
Then Put your Tome of Town Portal in the Horadric Cube with Wirt's Leg.
Then transmute them.
A portal wil open saying something along the lines of "Portal To Cow Level".
Or something like that.
PS:You get Wirt's Leg from the portal opened up by the Carin Stones.
(where you rescued Decard Kain)
Hope I helped.