Long-term oncological and functional results from a retrospective study on 469 patients over a 10-year period of subtotal laryngectomies (SL), 399 supracricoid partial laryngectomies (SCL) and 70 supratracheal partial laryngectomies (STL) are presented. The mean follow-up time was 97 months (range 60–165 months). Acute complications, types and rates of late sequelae, functional results, 2-year post-operative scores of laryngeal function and quality of life are reported. The observed long-term results were: SCL, 5-year overall and disease-free survival: 95.6, and 90.9%, respectively; 2-year post-operative laryngeal function preservation: 95.7%; STL, 5-year overall and disease-free survival: 80 and 72.9%, respectively; 2-year post-operative laryngeal function preservation: 80%. The performance status scale for laryngeal function preservation showed very high 2-year scores, with no significant differences depending on the type and extent of surgery. The adopted type of function-sparing surgery provided overall and disease-free survival rates that were somewhat better than those reported in studies based on organ-sparing protocols with chemoradiotherapy. The rate of total laryngectomy of completion in this series was 4.4%. A new classification of the current horizontal partial laryngectomies is also proposed, namely “Horizontal Laryngectomy System” (HOLS), based on the extent of surgical removal of laryngeal structures.