Determining differences in clinical outcomes of older adults treated at trauma centers (TCs) and nontrauma centers (NTCs) is imperative considering their persistent undertriage and the projected costs of fixing the problem. This study compared the incidence and predictors of complications and mortality among brain-injured older adults treated at TCs and NTCs. This secondary analysis of New York inpatient data included patients aged 55+ years, primary brain injury diagnosis, and acute care hospital admission. Interfacility transfers and nontraumatic brain injuries were excluded. International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) diagnosis codes identified complications and mortality. Injury severity was determined by mapping ICD-9-CM diagnoses to Abbreviated Injury Scale 2005 Revision 2008 dictionary scores. A subgroup analysis of 1,594 patients with New Injury Severity Scores greater than 15 was performed to examine complications and mortality. This study included 7,138 patients who met inclusion criteria. Predictors of subgroup complications included chronic renal failure, odds ratio (OR) = 2.251 (confidence interval [CI] = 1.470-3.447), p < .001; major operating room procedure, OR = 2.349 (CI = 1.679-3.285), p < .001; number of diagnoses, OR = 1.201 (CI = 1.158-1.245), p < .001; and number of procedures, OR = 1.119 (CI = 1.077-1.162), p £ .001. Mortality predictors included age, OR = 1.031 (CI = 1.017-1.045), p < .001; preexisting coagulopathy, OR = 1.753 (C = 1.130-2.719), p = .012; number of procedures, OR = 1.122 (CI = 1.081-1.166), p < .001; acute renal failure, OR = 3.114 (CI = 1.672-5.797), p < .001; systemic inflammatory response syndrome, OR = 4.058 (CI = 1.463-11.258), p = .007; adult respiratory distress syndrome, OR = 3.179 (CI = 1.673-6.041), p < .001; and subarachnoid bleed, OR = 2.667 (CI = 1.415-5.029), p = .002. Nearly 23% of the severely/critically injured patients experienced 1 or more complications. Incidence of complications was low and comparable for TCs and NTCs. The proportion of deaths was slightly higher at TCs but not significant. The most prevalent complications carry a high mortality risk.