Abstract: Coupled resonator circuits are of importance for the design of microwave filters, in particular, the narrow band bandpass filters. In this paper, the design method for microstripbandpass filters in terms of coupling coefficients and ex ternal quality factors is adopted to design a X band microstrip open loop cross coupled bandpass filter. Because of the cross coupling, a transmission zero is generated at each side of the passband which improves the selectivity and group delay of the filter. The cross coupled filter is designed and fabricated with RO5880 substrate, with arelative dielectric constant of 2. 2 and a thickness of0. 254mm. Simulation and measured results show that the filter has the characteristic of compact size, low in sertion loss, high selectivity and perfect out of band rejection.