To determine the occurrence of diarrhea and associated factors in critically ill patients with traumatic brain injury (TBI) in use of nutritional therapy. Prospective cohort study conducted in an Intensive Care Unit (ICU) of a General Hospital reference in trauma. We evaluated TBI patients who stayed less than 72 h in the ICU, who were using EN for at least 48 h. Definition of diarrhea it was considered three or more episodes of liquid stools or semi-liquid at 24 h. For analysis were evaluated demographic, epidemiological, clinical and nutritional data. Twenty-three patients were evaluated, being 86.9% male, median 33 years old (IQR = 25-52 years) and 16-day ICU stay (IQR = 10-26 days). Diarrhea occurred in 69.6% of the patients and they had a longer time in the ICU (p = 0.007). All patients who used combination prokinetic therapy (metoclopramide and erythromycin) and used antibiotics for more than 8 days had diarrhea (p = 0.057 and p = 0.007, respectively). The incidence of diarrhea was high in TBI patients with enteral nutrition and was associated with the use of antibiotics for more than one week.