A method of transmitting/receiving a data block is disclosed. In receiving at least one data block multiplexed to one physical channel, the present invention includes the steps of receiving control information for a data block transmission, checking whether there is a necessity for configuring a table having combination information of data block sizes internally, and configuring the table having the combination information of the data block sizes for a data block reception according to a result of the checking step. Accordingly, the present invention internally configures the CTFC information without receiving separate CTFC information, thereby facilitating the reception of data blocks.