An intake system for an engine includes an intake manifold having a surge tank room and branch passages, and a water-cooling type cooler having a first cooling unit and second cooling units. The surge tank room is disposed on a downstream side of a supercharger in a flow direction of intake air. Supercharged intake air flowing into the surge tank room is distributed among intake ports respectively through the branch passages. The first cooling unit is inserted in the surge tank room, and cools supercharged intake air which has flowed into the intake manifold through heat exchange between supercharged intake air and coolant flowing in the first cooling unit. The second cooling units are inserted respectively in the intake ports, and cool internal EGR gas, which has been recirculated into their corresponding intake ports, through heat exchange between internal EGR gas and coolant flowing in the second cooling units.