A method for transmitting a status report in a communication system based on multiple Radio Access Technologies (RATs) is provided. The method includes, when missing sequence numbers are detected from sequence numbers of packets stored in a reception buffer, identifying whether there are one or more sequence numbers which have not been received due to a transmission delay time difference between the multiple RATs in the missing sequence numbers, and when there are one or more sequence numbers in the missing sequence numbers, delaying transmission of the status report.