Mixer for an exhaust system of an internal combustion engine, comprising - a first mixer part with a plate-like body with an incoming flow side to be arranged oriented in the upstream direction with respect to an exhaust gas main flow direction and with an outflow side to be arranged oriented in the downstream direction with respect to the exhaust gas main flow direction, and - a second mixer part arranged on the outflow side of the first mixer part with a bottom wall arranged at a spaced location from the plate-like body of the first mixer part and with two side walls (28, 30), which extend starting from the bottom wall and extend towards the plate-like body of the first mixer part and are fixed at the first mixer part, wherein the second mixer part with its bottom wall and with its side walls (28, 30) and the first mixer part with its plate-like body define a reactant injection duct for receiving reactant in a reactant main injection direction, wherein at least one exhaust gas main passage opening open towards the reactant injection duct is provided in the plate-like body of the first mixer part and a plurality of exhaust gas secondary passage openings (78, 80, 82, 84, 86, 88, 90, 92) running past the reactant injection duct are provided, wherein the reactant injection duct is open in a first area of the outer circumference of the first mixer part at a receiving end for receiving reactant, and is open at a releasing end for releasing reactant or/and exhaust gas, characterized in that the bottom wall of the second mixer part extends at the releasing end with a bottom wall extension area beyond the side walls (28, 30) of the second mixer part. - a first mixer part with a plate-like body with an incoming flow side to be arranged oriented in the upstream direction with respect to an exhaust gas main flow direction and with an outflow side to be arranged oriented in the downstream direction with respect to the exhaust gas main flow direction, and - a second mixer part arranged on the outflow side of the first mixer part with a bottom wall arranged at a spaced location from the plate-like body of the first mixer part and with two side walls (28, 30), which extend starting from the bottom wall and extend towards the plate-like body of the first mixer part and are fixed at the first mixer part, wherein the second mixer part with its bottom wall and with its side walls (28, 30) and the first mixer part with its plate-like body define a reactant injection duct for receiving reactant in a reactant main injection direction, wherein at least one exhaust gas main passage opening open towards the reactant injection duct is provided in the plate-like body of the first mixer part and a plurality of exhaust gas secondary passage openings (78, 80, 82, 84, 86, 88, 90, 92) running past the reactant injection duct are provided, wherein the reactant injection duct is open in a first area of the outer circumference of the first mixer part at a receiving end for receiving reactant, and is open at a releasing end for releasing reactant or/and exhaust gas, characterized in that the bottom wall of the second mixer part extends at the releasing end with a bottom wall extension area beyond the side walls (28, 30) of the second mixer part.