A portable hydrogen fueled proton exchange membrane fuel cell (PEMFC) system was designed to meet the design constraints of the 1st International Association for Hydrogen Energy Portable Fuel Cell Design Competition that could be used to supply power to portable devices. The portable PEMFC stack has a physical dimension of 5.95 x 5.95 x 1.95 cm and 0.275 kg in mass. The PEMFC stack has a continuous output power of 12.5 W with a peak power output of 17 W. The fuel cell stack is an open cathode design which uses an external fan for both cooling and air supply. The fuel cell system includes an external fan along with power and control electronics that powers the fan and provides steady 5 V and 12 V outputs. The system also includes a standard USB connector for charging portable devices such as cellular phones and portable media players. A detailed description of the fuel cell stack and system design is presented along with experimental data demonstrating the stack and system performance.