A design procedure for fourth and sixth order ultra-wide band filter using step impedance resonators (SIR) is presented in this paper. SIR provides wide degree of freedom in structures and capable of handling wide frequency band. Due to these features and its simpler structure, it gives many possibilities for practical applications. In this paper, transfer function is extracted from equivalent circuit using even-odd mode analysis. Filtering function is formed to show maximum number of transmission poles in the passband. For optimum characteristic impedance values, extracted filtering function has been forced to form chebyshev type frequency response. Design of sixth order UWB filter is done to achieve better selectivity. Measured and simulated results show good agreement. © 2012 IEEE.