The invention relates to a prefabricated panel for light-weight one-way joist slabs of the compound section type, comprising an upper contributing layer, a lower contributing layer having a series of upper peaks and troughs and shear transfer bolts which secure the upper contributing sheet to the upper peaks of the lower contributing sheet, and shear bolts or pins which secure the lower contributing layers to the slab framework beam. The functioning of the upper and lower contributing layers as a compound section permits the production of a highly efficient system for supporting the requirements of bending and shear forces, having a low unitary weight in comparison to the existing systems, which involves lower loads in terms of its own weight and a reduction in the inertia effects during seismic events, while constituting a less bulky structural solution, having fewer ground requirements and being much more economical, thereby reducing the time and input, labour and equipment required for the production and assembly thereof.