—This paper presents a sampling frequency offset estimation in time domain for discrete multitone (DMT) systems. Cyclic prefix (CP) enables this estimation without pilots. The proposed algorithm realizes sampling frequency estimation on each sample within the last period where the CP copied from. The sampling-rate iteration method markedly improves acquisition speed and jitter performances. Simulations show that this method can synchronize DMT systems in both AWGN channels and twisted pair copper wires along with non-ideal factors. Practical examples of the veryhigh bit-rate digital subscriber lines (VDSL) are used to illustrate results.