Laryngeal Intraepithelial Neoplasia (LIN) is graded in 3 levels (LIN Grade I-II-III), corresponding to the classic aspects of mild, moderate and severe dysplasia-in situ carcinoma, on the basis of the number and position of mitoses and of the undifferentiated or atypical cells limited to the basal or extended to the intermediate or the superficial layers of epithelium. In order to reduce the subjective imprecision of these parameters we have applied not only traditional dimensional evaluators but also procedures of analytical morphometry to the nuclear shape. By using the software system S.A.M. (Shape Analytical Morphometry) we have examined fifty nuclei of the basal layer in LIN grade I, II and III, fifty nuclei in normal laryngeal mucosa and fifty nuclei in invasive carcinoma of the larynx (twenty-five cases in all). Normal and dysplastic nuclei did not show any dimensional differences, while the carcinomatous nuclei were significantly larger. An asymmetric distortion of the nuclear contour was noted in the moderate and severe dysplasia, but not in carcinomatous cells. Also the Fourier parameters, increased in severe dysplasia, decreased dramatically in carcinomatous cells which showed nuclei with minor contour irregularities than the normal cells. These findings outline the discriminative power of the analytical morphometry and suggest a possible correlation between nuclear shape and cell biology.