Abstract: The present invention relates to a process for manufacturing panels (9) for aeronautical structures with U-shaped stiffening members (13) and I-shaped stiffening members (17) between their webs comprising the following steps: providing laminates for shaping the skin (11) on the curing tool (31); providing planar laminates (23) for shaping the stiffening members (13, 17); shaping the U-shaped stiffening members (13) on individual shaping tools (33) and placing the I-shaped stiffening elements (17) in said tools; grouping said individual shaping tools (33) together on an assembly tool (41); placing the group of stiffening members (13, 17) on the skin (11); placing a vacuum bag (55) on the assembly with the aid of profiles (59); consolidating said assembly by means of a curing process under suitable pressure and temperature conditions using external tools (60) to assure verticality of the webs of the stiffening members (13, 17).