A method is presented to use an electron microscope in transmission mode to determine the mis-tilt from a zone axis of a crystalline material. The method involves recording a number of additional diffractiion patterns with incident beams tilted over 2 to 3 degrees. It is shown that an accuracy of 0.02 degree can be achieved, which is far better than that of the specimen-stage tilt axes, which is about 0.1 degree for the beta-tilt.@en