Purpose: To evaluate the physical and functional capacity and the risk of sarcopenia on the length of hospital stay and deaths in preoperative cancer patients. Methods: Preoperative patients admitted to the Cancer Hospital of Mato Grosso comprised the sample. Sociodemographic data, lifestyle data, and a questionnaire for sarcopenia screening were collected. Subsequently, total body mass, height, muscle strength, muscle mass, and physical performance were evaluated. The data were tabulated and analyzed using the statistical software SPSS (25.0). The signi cance level was 5%. Results: We observed 12 (7.4%) patients with low muscle strength, 20 (12.3%) patients with low muscle mass, 11 (6.8%) patients with low physical performance, and 18 (11.1%) patients with scores for possible sarcopenia. When the risk of sarcopenia was observed, 44 (27.2%) patients had at least one risk related to muscle disorder. When analyzing the prevalence and association of sarcopenia with sociodemographic variables, we observed that education level was associated with sarcopenia (p = 0.031). In addition, there was an association between preoperative sarcopenia and postoperative death (p = 0.006). Finally, there were important correlations between muscle strength and physical performance (p <0.05), between muscle strength and the sarcopenia questionnaire (p <0.001), and between physical performance and the sarcopenia questionnaire (p <0.05). Conclusion: The results suggest the need for counseling and the need to evaluate patients for risk of sarcopenia, since early intervention, such as dietary supplementation and physical exercise, may favor a better postoperative prognosis, possibly corresponding to shorter hospital stays and longer survival and quality of life for patients, especially those who will undergo surgical procedures.