Screw-spindle pump, particularly for cooling systems, comprising a first screw, a second screw and a pump housing inside which said first screw and said second screw are housed, between said first screw, said second screw and said pump housing being defined a plurality of pumping chambers adapted to move, as a consequence of the rotation of said first screw and of said second screw, a fluid from a suction area to a delivery area of said pump, wherein said pump housing comprises, in correspondence of respectively said suction area and said delivery area, a suction port and a delivery port both obtained in said pump housing, wherein said suction port consists of at least one suction through hole obtained in said pump housing and wherein said delivery port consists of at least one delivery through hole obtained in said pump housing, wherein said pump housing further comprises: - a base comprising a pair of thrust bearings protruding from said base towards the inside of said pump housing adapted to axially support respectively said first screw and said second screw housed inside said pump housing, - a hollow body in which said first screw and said second screw are housed; wherein said hollow body comprises said base and one or more side walls; wherein said suction port is obtained in said base; wherein said delivery port is in fluid communication with the internal volume of said hollow body; the screw-spindle pump being characterised in that said pump housing further comprises: - a flange, made as one piece with said hollow body and configured to be fixed to a motor for driving said first screw, wherein said delivery port being obtained in said flange; wherein said hollow body with its side walls, said base, said thrust bearings and said flange are made in one piece, as a single body, and wherein the central axes (151, 161) of respectively said suction through hole and said delivery through hole are parallel to each other and arranged according to an axial direction. - a base comprising a pair of thrust bearings protruding from said base towards the inside of said pump housing adapted to axially support respectively said first screw and said second screw housed inside said pump housing, - a hollow body in which said first screw and said second screw are housed; wherein said hollow body comprises said base and one or more side walls; wherein said suction port is obtained in said base; wherein said delivery port is in fluid communication with the internal volume of said hollow body; the screw-spindle pump being characterised in that said pump housing further comprises: - a flange, made as one piece with said hollow body and configured to be fixed to a motor for driving said first screw, - a flange, made as one piece with said hollow body and configured to be fixed to a motor for driving said first screw, wherein said delivery port being obtained in said flange; wherein said hollow body with its side walls, said base, said thrust bearings and said flange are made in one piece, as a single body, and wherein the central axes (151, 161) of respectively said suction through hole and said delivery through hole are parallel to each other and arranged according to an axial direction.