Background: Methods: ICU patients with PA were identified and classified as colonized or infected. Infected patients were reviewed for source, patient characteristics, antimicrobial susceptibilities, appropriateness of empiric antimicrobial therapy, and 30-day mortality. Independent predictors of mortality were identified using multivariable logistic regression. Results: One hundred forty (71%) patients with PA were infected. Mean patient age was 55 (SD 18) years; 62% were male. Admission categories included medical (71%), surgical (20%), and trauma or neurological (9%). Mean Acute Physiology and Chronic Health Evaluation (APACHE) II score was 19 (SD 10). One hundred twenty-six (90%) patients were mechanically ventilated, 102 (73%) required vasopressors, and 27 (19%) received renal replacement; 32 (23%) died within 30 days. Infection was nosocomial in 101 (72%) cases. Sources were respiratory (66%), skin-soft tissue (11%), urinary (10%), blood (5%), surgical (5%), gastrointestinal (2%), or unknown (1%). Twenty (14%) isolates were multi-drug resistant; 6 (4%) were extensively drug resistant. Empiric antimicrobial therapy was effective in 97 (69%) cases. Liver disease (adjusted OR [aOR] 6.2, 95% CI 1.5 to 25.7; Conclusions: PA infection in ICU is most commonly respiratory and associated with substantial mortality. Existing malignancy, liver disease, and higher APACHE II score were independently associated with mortality.