Yes, in most cases.  You have to be sure it is something that can withstand long cooking and not get overdone or dried out.  The crockpot produces it's own liquid so you have to be careful not to add as much liquid as you would on the stove.  Also, remember that proteins cook faster than starches in the crock pot.  Always put potatoes and hard vegetables on the bottom and meat or chicken on top.  I could function without my crock pots.