The prognosis of supraglottic cancer is worse than that of glottic cancer. Supraglottic cancers by subsites have different microenvironment of cancer cells, locoregional spread patterns. Therefore we presume that high therapeutic efficacy, while preserving the organ, can be obtained when supraglottic cancer is treated effectively according to its biological behaviors. For the purpose of determination of clinical characteristics and causes of treatment failures by subsites of supraglottis, the authors analyzed 24 cases(stage III 14 cases, stage IV 10 cases) of supraglottic cancer which were managed mainly by surgery in our institute. The results were as follows; 1) The suprahyoid group had worse pathologic grades, more frequent spread to hypopharynx, more freguent recurrence at primary site, and better three-year survival rate than the infrahyoid group. 2) The infrahyoid group had more frequent spread to glottis, understaging, recurrence at cervical nodes than the suprahyoid group. 3) There was no differences in nodal metastasis by sub sites. These results suggest that the suprahyoid group may have more aggressive spread pattern but better prognosis than the infrahyoid group.