In this work, the design procedure, modelling and implementation of recon¯gurable ¯lters based on RF microelectromechanical systems metamaterials is presented. Speci¯cally, tunable stop-band and pass-band frequency responses are obtained by combining RF-MEMS with metamaterials based in complementary split rings resonators. These particles, allow for the design of negative e®ective permittivity transmission lines, providing forbidden propagation frequency bands. Moreover, CSRRs properly combined with metal vias in transmission lines, generate a simultaneously " < 0 and ¹ < 0 e®ective media which involves an allowed frequency band. These two phenomenons have been used in order to implement stop-band and pass-band ¯lters. Since CSRRs present a LC-tank behaviour and are electrically coupled to the host line, the tunability is achieved by means of the RF-MEMS, which modify the electrical characteristics of the CSRRs and the electric coupling. A full electrical model for the description of the proposed structures is presented. The circuit model take into account the electrical characteristics of the RF-MEMS, CSRRs and transmission lines as well as the involved electromagnetic coupling and are used for accurate prediction of switchable ¯lters response.