This paper proposes a partial prediction approach for fast mode decision in H.264/AVC 4x4 intra-prediction, exploiting the inherent symmetry existing in the spatial prediction modes. The high compression efficiency of H.264 comes with a price of high computational complexity. The intra-prediction process with its robust full intra mode search rate distortion optimization (RDO) technique to select the best mode for each macroblock is one such computational bottleneck. Unlike many fast algorithms which search for dominant edge in each block the existence of which is never assured, our algorithm quickly tries to find a closer prediction mode for each 4x4 block using a simple cost measure derived from the symmetry in all the prediction modes. The proposed algorithm only searches 3 or lesser modes instead of 9 for the 4x4 luma blocks. Experimental results reveal the significant computational savings achieved with slight PSNR degradation and bit-rate increase.