A statistical comparison between histologic and radioclinical data was performed on a series of 120 cases of total laryngectomies in order to study the modes of invasion of laryngeal cancer and to quantify the differences of results as evaluated by pathological and by clinical examinations. The first part of this study deals with the spread of cancer depending on its site of origin; the second part examines spread regardless of the primary location of the laryngeal tumor. The comparative results show that it was difficult to determine the deep invasion of structures such as the preepiglottic space and the cartilages from the radio-clinical examination, especially in cases of cancer developed on a laryngocele. This study emphazises the importance of the histological examination of laryn-geal specimens as described here in order to codify the modes of invasion and, as a result, to help the otorhinolarynglologist in the choice of the best treatment. Cancer 38:346-360, 1976.