Disclosed is a SATA device having self-testing function with an OOB-signaling operation and a method of testing the same. The SATA device includes target and test-signaling controllers that sequentially generate and transceive control signals for the OOB-signaling operation. The SATA device also includes a test flow controller regulating the flow of the OOB-signaling control signals, and an analogue signal processor generating and transceiving analogue signals in correspondence with the OOB-signaling control signals. The analogue signals transmitted from the analogue signal processor return to the input terminal through a feedback loop.