A heat exchanger comprising a first heat exchange row and a second heat exchange row overlapping with each other, wherein each heat exchange row (10, 20) comprises a first header (11, 21) and a second header (12, 22) and a plurality of parallel, coplanar tubes interconnecting the first header (11,21) and the second header (12, 22), wherein the first header of the first heat exchange row and the first header of the second heat exchange row are enclosed between a first header plate and a first header tank that are fixedly connected to each other, wherein the second header of the first heat exchange row and the second header of the second heat exchange row are enclosed between a second header plate and a second header tank that are fixedly connected to each other, wherein a plurality of slots is formed in each of said header plates (41, 51), in each of which slots one end of a relevant tube is inserted, wherein one of said first header and second header of the first heat exchange row has an inlet of the heat exchanger and one of said first header and second header of the second heat exchange row has an outlet of the heat exchanger, wherein each header tank (42, 52) comprises two lateral edges (42a-42b, 52a-52b) fixedly connected to respective lateral edges of the relevant header plate (41, 51), and an intermediate edge (42c, 52c) fixedly connected to an intermediate portion (41c, 51c) of the relevant header plate (41, 51) in order to separate the respective headers of the first heat exchange row and of the second heat exchange row from each other, and wherein the intermediate edge (42c, 52c) of one of said first header tank and second header tank has a plurality of recesses establishing fluid communication between the respective headers of the first heat exchange row and of the second heat exchange row, said recesses defining fluid communication passages that are delimited, from opposite sides, by the intermediate edge (42c, 52c) of one of said first header tank and second header tank and by the intermediate portion (41c, 51c) of the relevant header plate (41, 51), characterized in that the intermediate edge (42c, 52c) of one of said first header tank and second header tank comprises two header wall portions which are spaced apart from each other, each of these header wall portions delimiting the relevant header of the first heat exchange row and, respectively, of the second heat exchange row, and an intermediate wall portion which interconnects the header wall portions, said recesses extending through said header wall portions and said intermediate wall portion. wherein the first header of the first heat exchange row and the first header of the second heat exchange row are enclosed between a first header plate and a first header tank that are fixedly connected to each other, wherein the second header of the first heat exchange row and the second header of the second heat exchange row are enclosed between a second header plate and a second header tank that are fixedly connected to each other, wherein a plurality of slots is formed in each of said header plates (41, 51), in each of which slots one end of a relevant tube is inserted, wherein one of said first header and second header of the first heat exchange row has an inlet of the heat exchanger and one of said first header and second header of the second heat exchange row has an outlet of the heat exchanger, wherein each header tank (42, 52) comprises two lateral edges (42a-42b, 52a-52b) fixedly connected to respective lateral edges of the relevant header plate (41, 51), and an intermediate edge (42c, 52c) fixedly connected to an intermediate portion (41c, 51c) of the relevant header plate (41, 51) in order to separate the respective headers of the first heat exchange row and of the second heat exchange row from each other, and wherein the intermediate edge (42c, 52c) of one of said first header tank and second header tank has a plurality of recesses establishing fluid communication between the respective headers of the first heat exchange row and of the second heat exchange row, said recesses defining fluid communication passages that are delimited, from opposite sides, by the intermediate edge (42c, 52c) of one of said first header tank and second header tank and by the intermediate portion (41c, 51c) of the relevant header plate (41, 51), characterized in that the intermediate edge (42c, 52c) of one of said first header tank and second header tank comprises two header wall portions which are spaced apart from each other, each of these header wall portions delimiting the relevant header of the first heat exchange row and, respectively, of the second heat exchange row, and an intermediate wall portion which interconnects the header wall portions, said recesses extending through said header wall portions and said intermediate wall portion.