Provided is a method for retransmitting data based on antenna scheduling in a MIMO system to which a spatial multiplexing technique is applied. The method includes the steps of: (a) at a transmitter side, modulating an input packet into transmittable data to transmit to a receiver side; (b) at the receiver side, estimating channel values from the packet transmitted from the transmitter side, and selecting transmitting and receiving antennas for transmitting the next packet from the estimated channel values; (c) detecting whether an error is present in the packet or not, and transmitting a feedback signal to the transmitter side, the feedback signal including information on whether or not to transmit the packet and a list of the selected transmitting antennas; and (d) at the transmitter side, retransmitting the transmitted packet or transmitting the next packet through the transmitting antennas designated by the receiver side depending on the feedback signal.