This paper presents the design, simulation and fabrication of a frequency selective surface (FSS) based unit cell structure over a flexible polyimide film for the effective electromagnetic absorption. The proposed FSS structure is designed using the splitted rings, where the unit cell dimensions are selected for effective EM absorption in the X band. The simulated results show absorption of 99.25% at 11.20 GHz having film thickness of 135 mu m. The proposed absorber film is effectively being used for the radar cross section (RCS) reduction of a cubical object. The proposed structure is fabricated and tested for the electromagnetic absorption as well as for the RCS reduction. A close match between the simulated and the experimental results is observed. The proposed FSS structure is ultrathin, flexible and flame retardant, which makes it a good potential candidate for the RF stealth technology.