Maxillary malignant tumor resection by maxillectomy might lead to defects that can be repaired by prosthetic obturation. The aim of this study was to associate quality of life (QoL) and the Obturator Functioning Scale (OFS) with functional performance and salivary flow rate in Brazilian patients rehabilitated with an obturator prosthesis. This retrospective cross-sectional study included patients who underwent surgical resection with or without radiotherapy or without chemotherapy and the rehabilitation with an obturator prosthesis at the Fundação Oncocentro de São Paulo (São Paulo, Brazil). The predictor variables were Performance Status Scale for Head and Neck Cancer Patients (PSS-HN) domains and clinical evaluation of salivary flow rate. The outcome variables were overall scores obtained by the University of Washington QoL Scale (UWQOL) and the OFS. Sociodemographics (gender and age) and clinical characteristics (postoperative radiotherapy, tumor stage, classification of maxillary defect, tooth in maxilla, and type of obturator) also were evaluated. Univariate and multivariate analyses were performed to determinate whether PSS-HN domains and salivary flow were predictors of overall QoL and overall OFS. The sample was composed of 73 patients with a mean age of 62years and 51% were men. According to the PSS-HN domains, some patients (5%) always ate alone, 87% reported that speech is usually or always understandable, and 56% had no dietary restrictions. Sixty-one patients (65%) reported some degree of hyposalivation. The mean overall QoL score was 76.5 (standard deviation, 5.3). Patients with compromised PSS-HN domains had significantly worse overall UWQOL scores (P= .001, P < .001, and P= .006, respectively). In multiple regression analyses, understandability of speech was the only predictor of overall QoL scores. The results of this study showed that understandability of speech was the only predictor of overall QoL scores.