Introduction: Several studies demonstrate a high rate of hospital malnutrition, which may be present at the time of admission or acquired during the hospitalization period, being considered an aggravating factor in the critical patient, causing increased morbidity and mortality, ventilation time and hospital stay. Objective: The objective of the present study was to evaluate the relationship between malnutrition and the clinical outcome of critically ill patients admitted to an ICU of a public hospital in DF. Methods: This is a retrospective cohort study, epidemiological, clinical and nutritional data were collected from patients' electronic medical records, and subsequently analyzed using the SPSS software. Results: 112 patients were included, mostly male (66%), the mean age of the patients was 54.7 years. Most patients had some degree of malnutrition on admission (59.8%), being more prevalent in patients aged 60 years or older, and in males. When analyzing the clinical outcome of patients, it can be seen that malnourished patients had a higher percentage of death (p <0.005). It was also observed that the presence of chronic non-communicable diseases was more prevalent in these patients (p = 0.005). Regarding pressure injury, no relevant statistical difference was found related to malnutrition. Conclusion: The present study was able to demonstrate how the occurrence of malnutrition within the ICU affects the clinical outcomes of patients, and the importance of improving nutritional assistance protocols aiming at qualified assistance to patients.