We have theoretically investigated the electronic structure of two coupled Si delta-doped GaAs at T = 0 K. For the uniform donor distribution we have studied the influence of donor concentration on the subband structure. In order to obtain the electronic structure we have calculated self-consistently the Schrodinger and Poisson equations. From the self-consistent calculation, we have seen that the electronic structure is quite sensitive to the donor concentration and the delta-layer separation. Under the assumption that the mobility is limited by the overlap of the wave function and the ionized scattering centers we can estimate that the mobility in single delta-doped structures is very low compared to closely spaced coupled delta-doped GaAs structures. (C) 2003 Elsevier Science B.V. All rights reserved.