Background This cross-sectional study objects to measure, subjectively and objectively, the voice and life quality of patients with oral cavity, pharyngeal and laryngeal cancer, after organ-preservation treatment. Methods 25 cases diagnosed and treated at a high complexity oncology center in southeastern Brazil. All had oral cavity, pharyngeal or laryngeal cancer, with a therapeutic proposal of radiotherapy alone or simultaneous radiochemotherapy. Acoustic voice analysis and the Voice Handicap Index protocol were used to measure voice quality. The data were analyzed through the χ2, Student's t and Kruskal Wallis tests. Significance level was 5%. Results After treatment, 40% complained of hoarseness, 56% complained of throat clearing, and no patient reported aphonia. On the voice quality auditory scale, 36% had moderate dysphonia. Acoustic voice analysis ranged from 184 to 221 Hz in females, and from 92 to 241 Hz in males. As for quality of life, most patients had mild physical, functional and emotional handicaps. Conclusions Chemio-radiation organ preservation protocols in the patients studied may leave the organ but with reduced function which brings communication sequelae. In such cases, voice assessment and quality of life protocols, as well as speech therapy rehabilitation, are important tools to preserve function, measure and treat alterations, and reintegrate patients into the community.