The development of non-precious metal catalysts (NPMCs) that are practical for use at the cathode of polymer electrolyte membrane fuel cells (PEMFCs) would provide immense economic advantages, perpetuating the looming widespread commercialisation of these devices. NPMC materials with excellent activity towards the oxygen reduction, coupled with PEMFC performance approaching that of state-of-the-art platinum catalysts brings this technology one step closer to practical application. Currently, the stability of these materials is still limited, and developing NPMC with excellent activity, performance and operational stability is the holy grail of PEMFC catalyst research. Fundamental knowledge available, along with recent progress made in this field of research will be the subject of this review paper.