We report the photoluminescence (PL) studies of two ultra-short type II GaAs/AlAs superlattices (SLs) deposed, respectively, on GaAs and Ga1-xInxAs substrates. The strain induced by the lattice mismatch involved by Ga0.88In0.12As substrate modifies the symmetry of the X conduction ground state in the opposed sense than that involved by the GaAs substrate. We have studied the effects of stress on the conduction and valence band structures. (C) 1999 Published by Elsevier Science Ltd. All rights reserved.