Intake manifold unit for an internal combustion engine of a motor-vehicle, configured for receiving and mixing a flow of recirculated exhaust gases and a flow of intake air, wherein said manifold unit comprises a manifold hollow body defining a chamber in communication with: - at least one conduit for introducing said flow of recirculated exhaust gases within said chamber of the manifold, - at least one inlet for the intake air of said internal combustion engine, - a valve located on the side of the at least one inlet, - a plurality of outlets in communication with the cylinders of the internal combustion engine for directing a mixed flow of air and recirculated exhaust gases towards the cylinders of the internal combustion engine, - said unit further comprising a baffle extending within said chamber and which defines a first chamber portion in communication with said inlet and with said conduit and a second chamber portion in communication with said plurality of outlets, - wherein said body has an elongated conformation defining a longitudinal direction of the manifold and said baffle extends within said manifold body parallel to said longitudinal direction of said body, starting from an end wall of the body where the inlet for the intake air is formed, up to a free end of the baffle located at a distance from a second end wall of said body which is opposite to the first end wall, wherein said conduit of the recirculated exhaust gases has a terminal end portion which is internal to said first chamber portion and which is directed transversally to the direction of the flow of intake air within said first chamber portion, said intake manifold unit being characterized in that said terminal portion of the conduit of the recirculated gases has a closed end wall and a lateral wall with at least one opening on an opposite side with respect to the air inlet, for directing the flow of recirculated exhaust gases within said first chamber portion in the same direction of the flow of intake air within said first chamber portion, in that said body of the intake manifold is constituted of plastic material and is formed by two half-shells (12, 13) welded to each other, in that said baffle is a substantially planar wall formed by two half-walls (51, 52) belonging respectively to said half-shells (12, 13) and having a line of mutual junction along a longitudinal median axis of the baffle, in that said manifold unit further comprises a temperature sensor and/or a pressure sensor located within said first chamber portion of said chamber, upstream to said terminal portion of the conduit of the recirculated exhaust gases, with reference to the direction of the flow of intake air. - at least one conduit for introducing said flow of recirculated exhaust gases within said chamber of the manifold, - at least one inlet for the intake air of said internal combustion engine, - a valve located on the side of the at least one inlet, - a plurality of outlets in communication with the cylinders of the internal combustion engine for directing a mixed flow of air and recirculated exhaust gases towards the cylinders of the internal combustion engine, - said unit further comprising a baffle extending within said chamber and which defines a first chamber portion in communication with said inlet and with said conduit and a second chamber portion in communication with said plurality of outlets, - wherein said body has an elongated conformation defining a longitudinal direction of the manifold and said baffle extends within said manifold body parallel to said longitudinal direction of said body, starting from an end wall of the body where the inlet for the intake air is formed, up to a free end of the baffle located at a distance from a second end wall of said body which is opposite to the first end wall,