This paper presents a novel Parallel-Coupled Microstrip Line (PCML) bandpass filter by etching of some slot resonators on the strip for suppressing the first spurious response. These slots perform a serious LC resonance property in certain frequency and suppress the spurious signals. Slot on the strip that is called Defected Microstrip Structure (DMS). The DMS interconnection disturbs the current distribution only across the strip, thereby giving a modified microstrip line with certain stop band and slow-wave characteristics. The measured results show a satisfactory rejection level more than 30dB at first spurious passband without affecting the passband response.