A method for foaming a hollow body, particularly a refrigerator cabinet, being closed in a containment mold, said hollow body including a first half-shell and a second half-shell (2") defining a foaming cavity having a prevailing length dimension (D L), wherein a highly reactive chemical mixture of a first and at least one second polymeric component is injected from a first end of said hollow body on an internal surface of the lower half-shell (2") by deposing it on different areas and letting it expand under vacuum conditions, wherein said hollow body, before being inserted in said containment mold, is pre heated, characterized by the steps of - keeping said internal surface of said hollow body suitably preheated by supporting it with a thermostating-supporting- table during the insertion and the permanence in said containment mold; - moving said thermostating-supporting-table, supporting said hollow body, from a position outside said containment mold to an internal position in which said hollow-body is housed in said containment mold, - circulating in said thermostating-supporting-table a heat transfer fluid provided by a thermal source for thermostating said hollow-body, said fluid flowing in conduits (13A, 13B) that are of flexible type for following a horizontal and vertical movements of said thermostating-supporting-table, - heating, or maintaining at an adequate temperature by said heat transfer fluid both said internal surface on which the resin is deposited and, by means of said flexible conduits, the other walls of said hollow body both during the insertion and stay in said containment mold, - keeping said hollow body enclosed within said containment mold in an air-tight condition, - injecting from said first end a first dosed quantity of reactive mixture generating a coherent jet of mixture having an initial value of mass flow rate (ṁ i) and average kinetic energy (E cin,sp) of the jet; - forming a mixture puddle in an intermediate area of said foaming cavity by keeping the coherence conditions of the mixture jet during the injection; - causing a forward sliding and a distribution of the mixture puddle (Z1, Z1') by means of the kinetic energy thrust of the jet towards a second end of said foaming cavity being opposite to said first end, and an extension of the puddle of mixture until the front reaches at least 50%, preferably at least 60%, of said length dimension (D L) of said foaming cavity; - continuing the injection of the reactive mixture and completing the introduction of resin needed to fill with over-packing the cavity of said hollow body by reducing the mass flow rate (ṁ i) and the average kinetic energy (E cin,sp) under coherence conditions of the jet, by keeping said hollow body thermostated and closed in said containment mold under conditions of internal pressure reduced with respect to the external environment during the expansion and polymerization of the reactive mixture. - keeping said internal surface of said hollow body suitably preheated by supporting it with a thermostating-supporting- table during the insertion and the permanence in said containment mold; - moving said thermostating-supporting-table, supporting said hollow body, from a position outside said containment mold to an internal position in which said hollow-body is housed in said containment mold, - circulating in said thermostating-supporting-table a heat transfer fluid provided by a thermal source for thermostating said hollow-body, said fluid flowing in conduits (13A, 13B) that are of flexible type for following a horizontal and vertical movements of said thermostating-supporting-table, - heating, or maintaining at an adequate temperature by said heat transfer fluid both said internal surface on which the resin is deposited and, by means of said flexible conduits, the other walls of said hollow body both during the insertion and stay in said containment mold, - keeping said hollow body enclosed within said containment mold in an air-tight condition, - injecting from said first end a first dosed quantity of reactive mixture generating a coherent jet of mixture having an initial value of mass flow rate (ṁ i) and average kinetic energy (E cin,sp) of the jet; - forming a mixture puddle in an intermediate area of said foaming cavity by keeping the coherence conditions of the mixture jet during the injection; - causing a forward sliding and a distribution of the mixture puddle (Z1, Z1') by means of the kinetic energy thrust of the jet towards a second end of said foaming cavity being opposite to said first end, and an extension of the puddle of mixture until the front reaches at least 50%, preferably at least 60%, of said length dimension (D L) of said foaming cavity; - continuing the injection of the reactive mixture and completing the introduction of resin needed to fill with over-packing the cavity of said hollow body by reducing the mass flow rate (ṁ i) and the average kinetic energy (E cin,sp) under coherence conditions of the jet, by keeping said hollow body thermostated and closed in said containment mold under conditions of internal pressure reduced with respect to the external environment during the expansion and polymerization of the reactive mixture.