A method for configuring a DRX (Discontinuous Reception) operation in a wireless communication system, and a wireless device therefore are discussed. The method includes, for example, receiving a first configuration for the DRX; starting a first onDuration timer according to the first configuration; receiving a second configuration for the DRX while the first onDuration timer is running; and stopping the first onDuration timer when the second configuration is received from the transmitter. At least one physical downlink control channel (PDCCH) is not monitored when the first onDuration timer is stopped. The first OnDuration timer is stopped without receiving a DRX Command medium access control (MAC) control element (CE). The method further includes starting a second onDuration timer according to the second configuration; and monitoring at least one PDCCH during an operation time of the second onDuration timer after the second onDuration timer starts according to the second configuration.