In this paper, we propose a new deinterlacing algorithm which is an edge dependent Interpolation (EDI) algorithm based on a horizontal edge pattern. Generally, a conventional EDI algorithm has a visually better performance than any other deinterlacing algorithm using one field. However, it produces unpleasant results due to the failure of estimating edge direction. In order to exactly detect edge direction, we use not only simple difference but also edge patterns. Experimental results indicate that the proposed algorithm outperforms conventional approaches with respect to both objective and subjective criteria. Index Terms I-to-P conversion, deinterlacing, edge dependent interpolation, edge pattern.