Small fuel cells are considered likely replacements for batteries in portable power applications. In this paper, the performance of a 2 cm×2.4 cm×1.4 cm passive miniature air breathing direct formic acid fuel cell (DFAFC) at room temperature is reported. The cell produced current density up to 250mA/cm2 and power density up to 33mW/cm2 at ambient conditions. The fuel cell runs successfully with formic acid concentration ranging from 1.8 and 10M with little degradation in performance. These results show that passive fuel cells can compete with batteries in portable power applications.