A new method of image comparison based on phase-only image processing has been applied to printed circuit board inspection. The technique has advantages over both standard template matching and rule-based approaches. The method makes use of a phase-only image comparison technique to compare a test board to a "golden board" image. Phase-only imaging is insensitive to translation errors (misregistration) between the golden board and the board under inspection. It is also very insensitive to lighting variations and can even handle cases of contrast reversal. The theoretical basis for the use of phase-only techniques will be presented. The results of applying this algorithm to real PCB inner layer images with simulated errors and image to image variations will also be shown.