A. method of preparing adipose tissue for transplantation, from lobular fat extracted, for instance, by liposuction, said fat consisting of a fluid component comprising an oily component, a blood component and/or sterile solutions and of a solid component comprising cell fragments, cells and one or more cell macroagglomerates of heterogeneous size, characterized in that it includes the steps of: - providing a washing and separating container having a washing chamber for washing the liposuctioned material, which container has an inlet and an outlet for the liposuctioned material to enter the washing chamber through the inlet and for at least part of said material, particularly the fluid component, to exit said chamber through the outlet, said washing chamber containing at least one stirring element; - providing size reducing means consisting of at least one series of parallel or intersecting sheets or wires that form at least one size reducing net located in said washing and separating container and/or a size-reducing container, - injection of the liposuctioned material in said washing and separating container, - injection of a sterile washing solution into the washing chamber of the washing and separating container, - dividing said fat into cell agglomerates smaller than said macroagglomerates, so that said cell agglomerates are as large as or smaller than a predetermined size, and so that they are on average of the same size, which size reducing step is carried out by causing said extracted lobular fat to pass at least once through said size reducing means, manual or mechanical stirring of the washing and separating container for obtaining an emulsion of the fluid components, such as blood fluids, blood residues, oils and other solutions contained in the liposuctioned material allowing said fluids to remain separate from the solid cell material without the use of enzymes or chemicals; - discharge of the liquid emulsion. - providing a washing and separating container having a washing chamber for washing the liposuctioned material, which container has an inlet and an outlet for the liposuctioned material to enter the washing chamber through the inlet and for at least part of said material, particularly the fluid component, to exit said chamber through the outlet, said washing chamber containing at least one stirring element; - providing size reducing means consisting of at least one series of parallel or intersecting sheets or wires that form at least one size reducing net located in said washing and separating container and/or a size-reducing container, - injection of the liposuctioned material in said washing and separating container, - injection of a sterile washing solution into the washing chamber of the washing and separating container, - dividing said fat into cell agglomerates smaller than said macroagglomerates, so that said cell agglomerates are as large as or smaller than a predetermined size, and so that they are on average of the same size, which size reducing step is carried out by causing said extracted lobular fat to pass at least once through said size reducing means, manual or mechanical stirring of the washing and separating container for obtaining an emulsion of the fluid components, such as blood fluids, blood residues, oils and other solutions contained in the liposuctioned material allowing said fluids to remain separate from the solid cell material without the use of enzymes or chemicals; - discharge of the liquid emulsion.