A method for transmitting and/or receiving wireless data and an apparatus therefor are provided. The method includes the steps of (a) when the length of a collection of data in an application layer is longer than the length of the payload of a protocol which the lower layer supports, dividing the collection of data into a plurality of protocol units, and transmitting the protocol units of data after adding at least one of the length information and location information of the data divided into the protocol units; and (b) determining whether or not a loss of data occurred, by referring to the information on the length and location of data divided into the protocol units in the step (a), and inserting blank data into the part corresponding to the lost data to re-form the entire collection of data.