This paper presents the numerical and experimental results of a miniaturized half-mode substrate integrated waveguide HMSIW C-band pass filter with defected ground structure DGS, using two slots and dumbbell shape defected ground structure. These two slots which are etched on the upper plane of the SIW cavity are used to constitute a multiplemode resonator, and the dumbbell-shape fractal DGS etched on the bottom plane can considerably enhance the filter's performances. The manufactured band-pass filter in half mode based on SIW technology has a size nearly half of that of a normal filter. The measurements results obtained by CST in C-band show that the manufactured filter has a large transmitted bandwidth of about 1.53 GHz from 5.97 to 7.5 GHz. The higher measured insertion is about −2.6 dB and the lower return loss measured is about −34 dB. The size of filter design achieved is 7.48 × 38.12 mm 2 which make it the more compact in comparison with some published works at the C-band frequency.