A method of reporting control information in a wireless communication system in which M downlink time divisional duplex (TDD) subframes are associated with an uplink TDD subframe. A user equipment (UE) receives resource allocation information used for a first physical uplink control channel (PUCCH) format. The UE selects a PUCCH format among a plurality of PUCCH formats including the first PUCCH format and a second PUCCH format. The second PUCCH format is selected if the UE receives a first physical downlink shared channel (PDSCH) in one of the M downlink TDD subframes on the primary cell. The UE receives a second PDSCH with a downlink assignment index (DAI) in one of the M downlink TDD subframes on the primary cell. The UE does not receive a first physical downlink control channel (PDCCH) corresponding to the first PDSCH on the primary cell.