Efficient transformation of yeast has been the corner stone of molecular studies in yeast for numerous years. It is essential for techniques such as the yeast two-hybrid system as well as genome modification. Here I present protocols for a number of different transformation applications. A quick and easy protocol is for situations in which large numbers of transformants are not required. The high-efficiency protocol generates large numbers of transformants from small amounts of DNA that can be scaled up for the library transformation protocol. A transformation protocol for a microtiter plate format is also included. Finally, a protocol for the production of frozen competent yeast cells is included, which allows cells to be taken from the freezer at a moment's notice and transformed with high efficiency.