Floating cover (1) for storage tanks (V) in general for substantially fluid material (R), comprising at least one covering element (2) of said storage tank, at least one floating structure (3) suited to support said at least one covering element and suited to ensure the flotation of said at least one covering element over the exposed surface (RI) of the material (R) contained in said storage tank, one or more means (5, 6) suited to heat the interior of said storage tank, and thus said material contained in said storage tank, said means (5, 6) being directly or indirectly mounted on said at least one floating structure (3). The covering element (2), made in whole or in part of heat-insulating material, in turn comprises at least one tarp suited to cover said exposed surface of the material and/or at least one rigid or semi-rigid dome-shape structure, suited to remain at least partly (21, 22) raised with respect to the exposed surface of the material forming a space (24) for the collection of the gas produced by said material.
