Abstract Background Nosocomial pneumonia (NP) remains a costly complication of hospitalization. Consisting of hospital-acquired ventilated (vHABP) and non-ventilated (nvHABP), and ventilator-associated (VABP) bacterial pneumonia, these conditions themselves are fraught with further complications. We examined hospital resource utilization (HRU) and the rates of important complications in these three groups in a large US database. Methods We conducted a multicenter retrospective cohort study within Premier Research database, a source containing administrative, pharmacy, and microbiology data. The three types of NP were identified based on a slightly modified, previously published ICD-9/10-CM algorithm,1 and compared with respect to hospital costs, length of stay (LOS) and development of C. difficile infection (CDI), extubation failure (EF), and reintubation (RT). CDI was identified by its treatment with metronidazole, vancomycin, or fidaxomicin. Marginal effects were derived from multivariable regression analyses. Results Among 17,819 patients who met the enrollment criteria, 26.5% had nvHABP, 25.6% vHAPB, and 47.9% VABP. Patients with nvHABP were oldest (mean 66.7+/-15.1 years) and those with VABP were youngest (59.7+/-16.6 years). vHABP was associated with the highest chronic disease burden (mean Charlson score 4.1+/-2.8) and VABP with lowest (3.2+/-2.5). Patients with nvHABP had lowest severity of acute illness (ICU 58.0%, vasopressors 7.7%), and those with vHABP were most likely to require vasopressors (38.8%). The adjusted EF and RT in vHABP and VABP, and CDI rates, and adjusted post-infection onset hospital LOS across all groups were similar. The adjusted marginal post-infection onset ICU LOS and total hospital costs relative to nvHABP were 5.9 (95% CI 5.4, 6.3) days and &6,814 (95% CI &3,637, &9,991) in vHABP, and 6.5 (95% CI 6.0, 6.9) days and &16,782 (95% CI &13,446, &20,118) in VABP. Conclusion Both HABP and VABP remain associated with significant morbidity and HRU in the US. VABP was associated with the longest post-infection ICU LOS and highest hospital costs. Reference 1. Zilberberg et al. Chest 2019;155:1119-30 Disclosures Marya Zilberberg, MD, MPH, Cleveland Clinic (Consultant)J&J (Shareholder)Lungpacer (Consultant, Grant/Research Support)Merck (Grant/Research Support)scPharma (Consultant)Sedana (Consultant, Grant/Research Support)Spero (Grant/Research Support) Brian Nathanson, PhD, Lungpacer (Grant/Research Support)Merck (Grant/Research Support)Spero (Grant/Research Support) Laura A. Puzniak, PhD, Merck & Co., Inc. (Employee) Andrew F. Shorr, MD, MPH, MBA, Merck (Consultant)