A system and a method that reports capability information regarding a dual mode User Equipment (UE) are provided. The UE supports Frequency Division Duplex (FDD) and Time Division Duplex (TDD). The UE capability transmitting method includes receiving a message requesting UE capability information from an evolved Node B (eNB), generating first capability information and second capability information according to the UE capability information requesting message, and transmitting UE capability information including the first and second capability information to the eNB. The first capability information comprises FDD capability information applicable to an FDD mode or TDD capability information applicable to a TDD mode. The second capability information comprises capability information applicable to both the FDD mode and the TDD mode. The system and method can allow a dual mode UE to efficiently report its capability information.