In the upcoming H.264, intra-prediction for 4×4 and 16×16 blocks is used to compress I-frame. However, we need to choose one of the 9 prediction modes for each 4×4 block. The full search (FS) algorithm to select the mode is computationally expensive. In this paper, an efficient intra-prediction mode selection (EIPMS) method is proposed based on partial computation of the cost function, selective computation of highly probable modes, early termination, and variable threshold setting. The proposed EIPMS can reduce the complexity considerably while maintaining similar PSNR and bit rate.