The development of next-generation resident registration cards, financial IC cards and administrative agency IC cards based on a smart card is currently coming out in Korea. However, the low-price IC cards without countermeasures against side channel analysis attacks are expected to be used fer cost reduction. This paper has investigated the side channel resistance of financial IC cards that are currently in use and have performed DPA attacks on the financial IC cards. We have been able to perform successful DPA attacks on these cards by using only 100 power measurement traces. From our experiment results, we have been able to extract the master key used for encryption of a count PIN number.