Thermal conductivity in GaN/AlGaN heterostructures is investigated by solving the steady-state phonon Boltzman equation in the relaxation-time approximation using phonon density of state, average group velocity and phonon relaxation time. In this paper dispersion curves, group velocity, density of states of energy, relaxation time of phonon and finally thermal conduction of several types of symmetric and asymmetric nanostructures are simulated. It has been concluded that proper selection of layer widths yields minimum thermal conduction in the considered structure. Also, making the structure asymmetric, affects the thermal conduction.© (2010) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.