This paper presents the numerical evaluation of the electromagnetic absorption at 900 MHz in a homogeneous human head model. Specific Absorption Rate (SAR) reduction in the head model is achieved by attaching nickel-zinc spinel ferrite sheet resonating at 900 MHz to a mobile phone with PIFA antenna. Simulations are performed to investigate the effect of various parameters like type of RF shield of thickness 1mm on the SAR using FEKO, the field simulation software. The SAR is obtained by calculating electric field strength at various points in the head model with and without RF shield. The E-field variation in the head model shows that RF shields reduce the SAR effectively.