Grey's Anatomy hottie Kate Walsh is back on the market ... in terms of real estate anyway!

Walsh has put her Spanish-style Los Angeles mansion for sale again at $3.995 million -- she paid $4.75 million for the 5,940-square-foot house in 2007.

The four-bedroom, four-and-a-half bathroom home was built in 1928. Walsh first put it on the market in May 2010, then took it off five months later.

Features include gorgeous stand-alone tubs, walk-in closets, pool, guest house, gym and more.