In this paper we study and compare bifurcation phenomena observed in the original Chua’s circuit and Chua’s oscillator with bifurcation trees constructed for three types of memristor oscillators derived from the original Chua’s circuit by replacement of nonlinear elements by a memristive element. Bifurcation phenomena observed are very rich and include period doubling sequences, period adding sequences, coexisting attractors, attractor collisions, periodic windows.