An apparatus to detect a sync signal, a VSB receiver using the same, and a method thereof. The apparatus includes a plurality of partial correlators to calculate a first partial correlation value between a sub sequence of a training sequence and an “I” signal of a received signal and a second partial correlation value between the sub sequence of the training sequence and a “Q” signal of the received signal, a plurality of squarers to square the first and second partial correlation values for each sub sequence, respectively, a plurality of adders to add the partial correlation values and to provide a correlation signal, a maximum value detection unit to detect a maximum one of the added partial correlation values, and a position detection unit to detect a position of the detected maximum value as the sync signal of the received signal.