A metallodielectric frequency selective surfaces (FSS) filter was optimized by a genetic algorithm (GA) to have dual stopbands in the mid-IR. Fabrication and measurement of this design demonstrated excellent filter properties with greater than 10 dB attenuation in the stopbands. However, blooming of the metallic patches resulted in a frequency shift in the measured response. Efforts are currently underway to improve the fabrication process so that the fabricated structures are faithful to the design parameters.