We have investigated the piezoreflectance spectra of the 1s Z(3) and Z(12) excitons in single crystals of copper chloride CuCl at 95 K with linearly polarized light. The spectra were studied for the applied low pressure p (p lower than 1 MPa) directed along the [001], [111] and [110] axis with the wave vector k of the incident light parallel to the [110] direction. A strong piezo-optical response is observed for the Z(3) exciton to regard to the one observed for Z(12). From the stress-induced shifts and splitting of the excitonic levels, we have been able to deduce the shear excitonic deformation potentials: b = (-0.18 +/- 0.02) eV and d = (0.30 +/- 0.03) eV. (C) 2005 Springer Science + Business Media, Inc.