This paper presents the development of a micro fuel cell (μFC) by polymeric micromachining technique. The membrane electrode assembly (MEA) is embedded in a gold-coated polymethyl methacrylate (PMMA) substrate, on which the gas flow channels are fabricated by laser micromachining. The special Gaussian shape of the microchannel allows the continuous sputtering of a gold layer, which works as the current collector for the fuel cell. The packed fuel cell has been characterized by an electronic load system. At room temperature, the power output of the 3 cm2 micro fuel cell can reach 315 mW cm−2 when hydrogen and oxygen are supplied to the anode and cathode, respectively. When air is used for the cathode side, the power output can reach 82 mW cm−2. During testing, the hydrogen flow is set to be dead-ended. That means the utilization of hydrogen in the μFC is close to 100%.