Abstract. In this paper, we propose a new motion estimation algorithm for motion-compensated frame rate up-conversion. To reduce computational complexity, it constructs a hierarchical structure using Gaussian image pyramid and unidirectionally estimates motion vectors (MVs) between two original frames at the top level. Since the accuracy of the motion vector may deteriorate at low resolution, each block has five candidates for motion vector so that disadvantages of hierarchical motion estimation are reduced. After motion estimation (ME), MVs of bottom level are corrected based on the sum of absolute difference (SAD) values of the blocks. All unidirectional MVs are assigned to bidirectional MVs, and new frames are interpolated using these MVs. As a result, proposed algorithm shows up to 1.3 dB increase in PSNR compared with conventional algorithm with low computational complexity, and it shows clearer images than conventional algorithms.