ITU-T H.264 MPEG-4 AVC includes weight prediction in inter prediction process to improve coding efficiency when encoding video with a fading scene. Weight prediction, however, increases complexity of motion estimation (ME) process significantly either in terms of additional operation or extra memory requirement. AVC standard performs weight prediction by scaling pixel value of the reference block to match with the fading effect. To follow this approach in ME, scaling operation has to be done at every pixel of all search blocks or pre-calculated before encoding. This paper proposes an efficient implementation method of weight prediction by scaling pixel value of the current block with an inverse of the weight factor instead. The proposed method reduces both the number of operations and memory requirement while sacrificing a negligible loss due to rounding error.