A method for aligning a phase plate within an electron microscope, wherein the electron microscope has an electron beam source for purposes of generating an electron beam, at least one lens for purposes of focusing the electron beam, and an image-recording unit for purposes of generating an image by detection of the electron beam, wherein by means of the phase plate a defined phase displacement is added to parts of the electron beam, comprising the following steps in the method: relative alignment of the phase plate with respect to a focal plane of the lens, lateral positioning of the phase plate within the focal plane, after the specimen to be investigated has already been inserted into the electron microscope and positioned in the latter, wherein at least one image is recorded by means of the image-recording unit, and a correction value is determined by means of an automated image-analysis method, alteration of the lateral position of the phase plate as a function of the correction value, characterised in that, for purposes of determining the correction value the following steps in the method are executed: adjustment of the lens to a first focal length (f 1) and the subsequent recording of a first image, adjustment of the lens to a second focal length (f 2) and the subsequent recording of a second image, wherein the first focal length (f 1) differs from the second focal length (f 2), and the first focal length (f 1) and the second focal length (f 2) are not equal to the optical distance (f 0) between lens and phase plate, automated evaluation of the first image and the second image by means of the image-analysis method, and determination of the correction value. relative alignment of the phase plate with respect to a focal plane of the lens, lateral positioning of the phase plate within the focal plane, after the specimen to be investigated has already been inserted into the electron microscope and positioned in the latter, wherein at least one image is recorded by means of the image-recording unit, and a correction value is determined by means of an automated image-analysis method, alteration of the lateral position of the phase plate as a function of the correction value, characterised in that, for purposes of determining the correction value the following steps in the method are executed: adjustment of the lens to a first focal length (f 1) and the subsequent recording of a first image, adjustment of the lens to a second focal length (f 2) and the subsequent recording of a second image, wherein the first focal length (f 1) differs from the second focal length (f 2), and the first focal length (f 1) and the second focal length (f 2) are not equal to the optical distance (f 0) between lens and phase plate, automated evaluation of the first image and the second image by means of the image-analysis method, and determination of the correction value. adjustment of the lens to a first focal length (f 1) and the subsequent recording of a first image, adjustment of the lens to a second focal length (f 2) and the subsequent recording of a second image, wherein the first focal length (f 1) differs from the second focal length (f 2), and the first focal length (f 1) and the second focal length (f 2) are not equal to the optical distance (f 0) between lens and phase plate, automated evaluation of the first image and the second image by means of the image-analysis method, and determination of the correction value.