Abstract: An aircraft rotor blade having a root portion having a through seat and designed for connection to the rotor; and a main portion extending from the root portion. The blade is produced by polymerizing an assembly having a main structure of composite material, and a composite material covering defining the outer surface of the blade. At the root portion, the main structure has a contoured block; and a lamina member extending about at least part of the block, and having a first part adhering to a first peripheral portion of the block, and a second part spaced apart from and facing a second peripheral portion of the block to form the seat; the lamina member having a pre-preg of continuous unidirectional fibers.