The invention relates to a method for detecting and classifying foreign material in an inspection lot of textile fibers that is moved lengthwise. The aim of the invention is to allow for the simultaneous inspection of the inspection lot with regard to a plurality of properties and to allow for the detection of a foreign material and for its classification in a simple manner while taking due consideration of all properties measured. According to the invention, values for deviations of these properties from a standard are detected and stored for at least two properties that are influenced by the foreign material. The values for the deviations are eliminated according to a predetermined rule except for the values of one property. A value for the deviation and a value for the length of the deviation on the inspection lot resulting from the values of the remaining property is detected and the foreign material is classified according to this deviation and length.