In 1971 Buttrose was chosen as founding editor of a new Australian women's magazine. This was originally to have been an Australian edition of the renowned American magazine "Cosmopolitan", but the deal fell through after Hearst Magazines sold the "Cosmopolitan" rights to longtime Packer rivals Fairfax, so Packer and Buttrose set about creating a new publication, dubbed "Cleo", which they launched in 1972, several months ahead of its rival. "Cleo" was an instant hit, selling its entire original print run in just two days; the magazine broke new ground in Australian mainstream publishing, featuring the first nude male centrefold (actor Jack Thompson) and frank articles on female sexuality and other topics, leading to the inclusion of the first sealed section in an Australian magazine. During the early months of the magazine, Buttrose became pregnant with her second child, Ben, but with the grudging support of the Packers she worked through her pregnancy; an unusual feat for that time as it was still common for women to have to give up work permanently after they became pregnant.