Abstract: A tube for a heat exchanger comprises a plate provided with a plurality of parallel flow ports, wherein the plate is formed by a single folded-up metal sheet and consists of an envelope formed by a first portion of the metal sheet, and of a partition structure formed by a second portion of the metal sheet, which extends in an corrugated manner within the envelope so as to define said flow ports therewith, and wherein the partition structure has a substantially polygonal profile having connection segments interconnecting opposite walls of the envelope and being interposed between adjacent flow ports. The connection segments are slanted relative to the opposite walls of the envelope, thereby defining an angle a>0° relative to the normal to said walls.