An apparatus and method for image interpolation based on low pass filtering are provided. The apparatus includes an edge direction detector detecting an edge direction for a pixel nearest to a to-be-interpolated pixel among pixels and determining the edge direction of the to-be-interpolated pixel as the detected edge direction, a pixel value calculator calculating pixel values of interpolation points located in a lattice filtering window having a predetermined size by using pixel values of pixels located adjacent to the interpolation points, and a filtering unit performing low pass filtering on the to-be-located pixel according to a low pass filter corresponding to the determined edge direction of the to-be-interpolated pixel, the low pass filter being one of low pass filters corresponding to predetermined vertical, horizontal, left diagonal and right diagonal directions respectively. Accordingly, a process of calculating the pixel value of the to-be-interpolated pixel can be simplified and a processing speed can be increased. Furthermore, it is possible to obtain a high-quality image without having image deterioration such as blocking effect caused by an error in a pixel value even for a region with an uneven edge.