Presented for the first time is a metamaterial transmission line that combines complementary split ring resonators (CSRRs) and RF microelectromechanical systems (RF-MEMS). The device consists on a coplanar waveguide structure loaded in its central strip with CSRRs embedding RF-MEMS variable capacitors. Owing to the presence of the CSRRs, the structure behaves as a stop-band filter. Through the actuation of the electrostatic RF-MEMS devices, the electrical characteristics of the CSRRs are modified so that their resonance frequency, and as a result the central frequency of the stop-band filter, can be tuned. This is the first time that an RF-MEMS tunable metamaterial-based filter has been designed for operation at Q-band.