All standard size Mattress will work.. The size of the mattress will be smaller than the actual dimension of the crib that you are giving as the mattress will be going inside the crib it self.

A good mattress for that crib would be the Safety 1st Heavenly Dreams White Crib Mattress

see here : http://www.amazon.com/gp/product/B004044...

A standard crib mattress will fit. If you look at other cribs on Walmart.com, none of them are the same length and width of the mattresses. This is because the measurements are probably taken from the outside of the crib, but the mattress will fit in the smaller inside dimensions.

If you check different websites (toys r us, sears.com etc) you will find this same thing, the dimensions of the cribs are slightly larger than the crib mattresses.

Try www.craigslist.com

I bought a crib online, but I'm having trouble finding a mattress to fit the crib. The description says that any standard size crib mattress will fit it, but when I look at any given mattress, the Length, Width, and height don't match the crib i ordered :( Can someone please help?

Here is a link to the crib I bought

http://www.walmart.com/ip/Dream-On-Me-Classic-2-in-1-Convertible-Crib-in-Pecan/13278316