Abstract: A method of downhole cyclone oil/water separation is described. Firstly, place a cyclone separator downhole in an oil well producing a mixed stream of oil, water and gas. The cyclone separator includes a separation chamber wherein liquids of differing densities are separated, at least one mixed liquids inlet through which liquids pass into the separation chamber, a first outlet for liquids of a first density range to pass from the separation chamber and a second outlet for liquids of a second density range to pass from the separation chamber. Secondly, connect the first outlet to a recovery conduit extending to surface. Thirdly, connect the second outlet to a disposal conduit extending to a selected disposal site. Fourthly, connect the mixed liquids inlet to pumping means and pump a mixed stream of oil, water and gas into the separation chamber of the cyclone separator.