Summary: We present chaotic dynamics of a particular non-linear oscillator having Duffing type stiffness, van der Pol damping and dry friction. We first utilize an averaging technique to obtain informations regarding the bifurcation behaviour of the vibrating system and then we analyze numerically the chaotic behaviour of the oscillator for parameters near bifurcation curves. We also discuss and illustrate the influence of the dry friction on the behaviour of a strange chaotic attractor.