A sheet processing machine, in particular a sheet-fed printing press or a sheet die cutting machine, has a sheet infeed having at least one stop for feeding and aligning sheets, and has a device for monitoring sheet travel along a sheet transport path of the sheet infeed. At least one measurement system, for detecting a lateral sheet edge of the sheet, is provided. A method is also provided for monitoring sheet travel along a sheet transport path in a sheet infeed. An alternative device and an alternative method for monitoring sheet travel along a transport path of a sheet processing machine are provided. At least one sensor, which can be associated with the lateral region of the sheet transport path, and which is configured for the optical detection and determination of the position of a mark on the sheet, is utilized.