The invention relates to a screw press for separating liquids from a suspension, in particular a sludge or fibrous suspension, said screw press comprising a conical or cylindrical and perforated casing (2) mounted in a housing (1) and comprising at least one cylindrical or conical screw shaft (3) that rotates in the casing (2) and that has at least one screw flight (4), wherein the suspension is pressed from a inlet opening (7) to an outlet opening (8) through an annular gap (5) formed between the casing (2) and the screw shaft (3) . The efficiency of the drainage should thereby be improved in that at least one screw flight (4) has at least one axial opening (6).
