Miniaturized fuel cells as compact power sources fabricated in Pyrex glass using standard polymer electrolyte membrane (PEM) and electrode materials are presented. Photolithographic patterned and wet chemically etched serpentine flow channels of 1 mm in width and 250 μ m in depth transport the fuels to the cell of 1.44 cm2 active electrode area. Feeding H2/O2 a maximum power density of 149 mW cm−2 is attained at a very low Pt loading of 0.054 mg cm−2, ambient pressure, and room temperature. Operated with methanol and oxygen about 9 mW cm−2 are achieved at ambient pressure, 60 ° C , and 1 mg cm−2 PtRu/Pt (anode/cathode) loading. A planar two-cell stack to demonstrate and investigate the assembly of a fuel cell system on Pyrex wafers has successfully been fabricated.