The approach of somatic cell and molecular genetics for the study of intracellular regulation of cholesterol metabolism has blossomed in recent years. This review lists all the Chinese hamster ovary cell mutants involved in cholesterol metabolism. In addition, it summarizes the characteristics of mutants involved in three different processes: (1) sequential cleavage of the membrane-bound sterol regulatory element-binding proteins; (2) cholesterol esterification; and (3) intracellular cholesterol transport from the lysosome/endosome.