A novel dual-mode bandpass filter using defected microstrip structure with distributed capacitance loading inside the free area of a defected microstrip dual-mode loop resonator is proposed in this paper. The filter has the advantages of compact size together with sharp rejection of out-bands and a wide stop-band. The measured results show that better than 20dB rejection levels in the stop-band up to 4.25 GHz have been obtained. It has been validated by simulation and experiment. The simulated results are compared with measured data and a good agreement is achieved.