An interleaver is disclosed for a turbo encoder in an UMTS. The interleaver includes a register for updating and registering a plurality of parameters for setting an operating condition of the interleaver; a controller for generating a control signal for controlling an operation of the system by receiving the operating condition from the register; an address calculator for generating a finally interleaved address using an inter-row permutation pattern T(j), an intra-row permutation pattern increment arrangement value incr(j) and an intra-row permutation basic sequence s(i), provided from the register according to the control signal generated by the controller; and a data storage for sequentially storing data input to the turbo encoder and outputting data corresponding to the address generated by the address calculator.