In general the assessed value is lower than the market value, but in this enviroment that could be the wrong information. Your area could have a lot of REO or short sales happening and the value of your home could be lower than the assessed value. It would be wise to get a free market analysis from a local Realtor. Even go so far as to get one from a competing office so you could assess the value. you are under no obligation to either and you may just get more information about the market and value of your property than you expect.