OBJECTIVE: The aim of this study was to explore the relationship of intracranial pressure (ICP) with intensive care unit (ICU) length of stay in a large cohort of severe traumatic brain injury patients and identify factors associating with prolonged ICU course. METHODS: This was a single-center database review of de-identified research data that had been prospectively collected; setting: neurosurgical ICU, Ben Taub General Hospital, Houston, TX. RESULTS: In a cohort of 438 severe traumatic brain injury (TBI) patients, 149 (34%) had a motor Glasgow Coma Scale score of 1 to 3 on admission and 284 (65%) had 4 to 5. Intracranial pressure during the ICU course was 19.8±11.2 mm Hg. Favorable outcome was obtained in 148 (34%), and unfavorable, in 211 (48%) patients with a mortality of 28%. ICU length of stay (LOS) was 19.4±13.9 days. Joint modeling of ICP and ICU LOS was undertaken, adjusted for the International Mission for Prognosis and Analysis of Clinical Trials in TBI admission prognostic indicators. A higher ICP was not significantly associated with longer ICU LOS (P=.4). However, presence of a mass lesion on admission head computed tomography was strongly correlated with a prolonged ICU LOS (P=.0007). Diffuse injuries with basal cistern compression or midline shift were marginally associated with a longer ICU LOS (P=.053). CONCLUSIONS: ICP, as monitored and managed according to BTF guidelines, is not associated with ICU length of stay. Patients with severe TBI and a mass lesion on admission head computed tomography were found to have prolonged ICU LOS independently of other indicators of injury severity and intracranial pressure course.