We propose an ultra-low memory fingerprint matching algorithm and implement it on a 32-bit smart card. We first evaluated both the number of instructions executed and memory requirement of each step of a typical fingerprint matching algorithm. Then, we developed a memory-efficient algorithm for the most memory-consuming step (alignment) by doing more computations under the restriction of the real-time requirement. Our experimental results show that the proposed algorithm can reduce the required memory space by a factor of 62 and can be executed in real-time on a 32-bit smart card.