When an animal is exposed to high hydrostatic pressure, its cellular membranes1,2, proteins3,4,5 and DNA6 are damaged. At pressures of around 30 megapascals (MPa), proliferation and metabolism in micro-organisms stops; at 300 MPa, most bacteria and multicellular organisms die. But here we show that, in perfluorocarbon at pressures as high as 600 MPa, small terrestrial animals known as tardigrades can survive in a dehydrated state.