As part of research into automated document imaging, an algorithm has been developed to detect the orientation (portrait/landscape) of a binary image page. The detection is based on an analysis of projection profiles, vertical and horizontal variances on a page, and a technique to reduce the impact of non-textual data (blanks, graphics, forms, line art, large fonts, and dithered images) from the page orientation result. The algorithm performed well on test images independent of text dominance. The performance of the algorithm has been evaluated using a sample size of several thousand images of medical journal pages. The algorithm is capable of detecting the page orientation at an accuracy rate of 99.92 - 99.93%.