This chapter introduces the materials, fuels, and oxidants exploited for membraneless laminar flow-based fuel cells (LFFCs), also known as microfluidic fuel cells. Membraneless LFFCs benefit from the lamination of multiple streams in a microchannel. The lack of convective mixing leads to a well-defined liquid- liquid interface. Generally, microfabrication techniques or fast prototyping process such as laser machining or micromolding can be used to make the channel. To fabricate the electrodes, besides conventional methods, such as painting and spraying of catalyst particles, electrodeposition, sputtering, and Ebeam evaporation techniques can be used to fabricate a thin layer of catalyst or metallic current collector. Electrodes are positioned at two sides of the liquid- liquid interface. This interface is considered as a virtual membrane and ions can travel across the channel to reach the other side and complete the ionic conduction. This chapter explains and compares the performance of membraneless LFFCs based on their design, and some constrains on materials are discussed for future development and commercialization.