A method for decorating in thickness a ceramic slab, comprising the following steps: preparing, on a decoration surface (10), a first soft decorated layer (L1) of ceramic material endowed with a decoration (V); progressively transferring, by deposition, the soft decorated layer (L1) from the decoration surface (10) to a first deposition surface (50), situated at a lower height than the decoration surface (10), thus progressively forming on the first deposition surface (50) a second soft decorated layer (L2) which has a head (H) and a tail (T); progressively transferring, by deposition, the second soft decorated layer (L2) from the first deposition surface (50) to a second deposition surface (83), situated at a lower height than the first deposition surface (50), starting from the tail (T) of the second soft decorated layer (L2), thus progressively forming on the second deposition surface (83) a third soft decorated layer (L3).