A method and system for measuring lithographic image foreshortening. The method comprises the steps of providing a critical dimension scanning electron microscope, and using that critical dimension scanning electron microscope to measure lithographic image foreshortening. Preferably, a defined feature is formed using a lithographic process, and the critical dimension scanning electron microscope is used to measure foreshortening of that feature. For example, the feature may be a line, and the critical dimension scanning electron microscope may be used to measure foreshortening of the line. Also, the feature may be two arrays of lines, and the critical dimension scanning electron microscope may be used to measure the separation distance between the arrays. That separation distance may be used to determine a focus of the lithographic process.