This paper presents a novel V-band coplanar waveguide low pass filter based on defected ground structure (DGS) cells. The proposed DGS cell provides low-pass characteristic whose cutoff frequency could be changed by tuning its dimensions. To realize a low pass filter with excellent rejection in the stop-band, several DGS cells with different sizes are cascaded together. Gallium arsenide is adopted to be the substrate of the low-pass filter with the cutoff frequency located in the V band. By optimization, a low-pass filter with the cutoff frequency of 60 GHz is designed, whose insertion loss in the pass band is less than 0.2 dB and the rejection in the stop-band is better than 25 dB from 65 GHz to 100 GHz.