This paper describes a new algorithm for disparity estimation using trinocular stereo. The three cameras are placed in a right angled configuration. A graph is then constructed whose nodes represent the individual pixels and whose edges are along the epipolar lines. Using the well known uniqueness and ordering constraint for pair by pair matches simultaneously, a path with the least matching cost is found using dynamic programming and the disparity filled along the path. This process is repeated iteratively until the disparity at all the pixels are filled up. To demonstrate the effectiveness of our approach, we present results from real world images and compare it with the traditional line by line stereo using dynamic programming.