Background: The knowledge of bedside diagnostic EUS in critically ill patients is limited. Objective: To investigate the indications, feasibility, safety, and clinical utility of diagnostic EUS in the intensive care unit (ICU). Design: Retrospective. Setting: Tertiary-care referral teaching hospital. Patients: All consecutive patients who had EUS done in the ICU within a 6-year period. Intervention: Bedside EUS and EUS-guided FNA. Main Outcome Measurements: EUS indications, complications, and impact on management. Results: A total of 64 EUS procedures were performed in 63 patients (38 men, 25 women; age range 27-78 years); 1 patient underwent 2 separate EUS procedures. EUS was performed while the patients were mechanically ventilated in 70% (45/64) of cases. Indications for EUS included jaundice (n = 24), mass of unknown etiology (n = 25), unexplained pancreatitis (n = 7), and staging of known cancer (n = 3). In 5 cases, EUS was used as an alternative to other imaging modalities because of morbid obesity (n = 3) or contraindication to intravenous contrast material (n = 2). Complications included reversible oxygen desaturation (n = 4), nonsustained ventricular tachycardia (n = 1), and transient hypotension (n = 1). Overall, EUS influenced management in 97% (62/64) of cases. Limitations: Retrospective, single-center study. Conclusion: ICU-based EUS can be performed with few intraprocedural complications and can be a valuable diagnostic modality in the ICU setting. It appears to be particularly useful for determining the etiology of jaundice, masses of unknown etiology, and pancreatitis. It may have particular value as a diagnostic technique on selected patients with unstaged cancer and when morbid obesity or the inability to use intravenous contrast material precludes the use of other imaging modalities in the critically ill patient.