We present preliminary results towards realization of three dimensional material implication logic with monolithically stacked TiO2-based memristive devices. As a first step towards our goal we have fabricated and successfully demonstrated resistive switching for top and bottom layer memristors of the bilayer device stack. The 3D aspect of the circuits, which is a main novelty of our work, enables much higher performance of implication logic as compared to planar case. More generally, our research could be applied to digital memories and hybrid programmable logic which would benefit from 3D monolithical integration.