The Hall resistance ρxy of thin films of the Bi2Se3 topological insulator with a thickness from 10 nm to 75 nm at a temperature of 4.2 K and in magnetic fields up to 10 T has been measured. The size effect was found, i.e. dependence of the Hall resistance and the Hall coefficient on the thickness of the studied films. Using a single-band model, the values of the current carrier concentration and their mobility are calculated, which also change with a change in the thickness of the samples.