Abstract We present an investigation of non-equilibrium LO-phonon effects in quantum well systems. Phonon confinement is taken into account by considering esplicitly slab modes in the formulation of Fuchs and Kliever. With respect to the “standard” case, where a tridimensional dispersion is used for the LO phonons, the electron-phonon interaction is riduced as result of phonon confinement. We use the Monte Carlo (MC) scheme, which allows the simultaneous study of the coupled electron and phonon dynamics, without requiring any sort of assumption on the respective distribution function. It should be pointed out that the quantization of the phonon wavevector in the direction perpendicular to the interface completely solves the normalization problems of the hot-phonon calculation in 2D-systems. For the case of photoexcitation in AlGaAs-GaAs quantum wells we observe a reduction in the cooling rate due to the reabsorption of hot phonon.