This paper presents a new class of triple mode dielectric resonator filters. These devices use dielectric-loaded cavities with unloaded Q-factor of 3000–5000 and reasonable spurious free window. The proposed structure is less than one quarter of the physical volume of TEM filters of the same Q. A finite element method solver for electromagnetic structures (HFSS) is used to study the main properties of this resonator. Fundamental design rules for a bandpass filter have been presented. A three pole bandpass filter was designed, fabricated and measured to verify the proposed approach.