New dual-mode bandpass waveguide elliptic filters with the added advantage of easy fabrication by milling are introduced. The filters have an in-line configuration in which the dual-mode cavities are kept homogeneous with no intracavity coupling elements. Coupling between adjacent cavities is implemented by rectangular irises, which are placed at the center top of the cross section. The structure can be fabricated as a single piece which is completed by a metallic cover plate. Example filters are designed to show the performance of this class of dual-mode filters. © 2006 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2007.