Аннотация:Quantum Hall effect and Shubnikov-de Haas oscillations in a 2D hole gas at a p-GaAs/Al0.5Ga0.5As (001) interface show, that under in-plane (110) uniaxial compression a redistribution of carriers between the two spin-splitted subbands of the ground heavy hole state takes place. At the maximal compression of 2.5 kbar the carrier density of the most populated subband is decreased by 18%, while the total carrier density remains almost unchanged. A decrease of the spin-splitting under the uniaxial compression is proposed.