We performed a series of Raman and photoreflectance measurements on several InxGa1-xAs/GaAs strained layer superlattices of the same period but of different alloy compositions and substrate orientations. Both types of measurements are used in order to estimate the in-plane strain in these layers. The values obtained by both methods are in good mutual agreement, thus showing that photoreflectance is an effective method for strain determination. © 1993 Academic Press. All rights reserved.132189