A method for 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 a solid component comprising cell fragments, cells and one or more cell macroagglomerates of heterogeneous size, wherein it includes the step of 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 size reducing means (3) consisting of at least one series of parallel or intersecting sheets or wires that form at least one size reducing net located in a washing and separating container (1) and/or a size-reducing container (2).
