In this paper, we present a new microstrip stepped impedance interdigital bandpass filter with tapped square split ring resonators (T-SSRR). The quarter wavelength stepped impedance resonators (λ/4-SIR) allow a higher f/fo ratio as compared with the conventional unit impedance resonator (UIR), thus extending the rejection band. Moreover, the T-SSRR which is shown to be a wide band bandstop filter with three transmission zeros, suppress the spurious passband and extend the stopband further. To verify the proposed structure usefulness, two prototype 3^rd order λ/4-SIR bandpass lilters, with and without T-SSRR, have been designed at 525MHz with 6.5% bandwidth. Demonstrated is a good spurious suppression of -30dB at ft, and the rejection band is wider than 5.8fo with the fundamental passband almost unaltered.