Objective <p>The number of nonagenarians presenting to emergency departments (EDs) worldwide is rapidly increasing. These demographic faces unique challenges, including atypical clinical presentations, frailty, and a high burden of comorbidities. Despite their vulnerability, limited data exist on factors influencing survival in this group. This study aimed to identify prognostic factors affecting survival among nonagenarian patients admitted to the ED, focusing on clinical, biochemical, and treatment variables.</p> Methods <p>A retrospective review was conducted, analyzing data on demographics, comorbidities, medication use, laboratory values, and hospital stay length for nonagenarian patients admitted to the ED at Göztepe Prof. Dr. Süleyman Yalçın City Hospital from 2020 to 2023. Survival analysis utilized Kaplan-Meier and Cox regression methods, with statistical significance set at <i>p</i> &lt; 0.05.</p> Results <p>Among 316 patients (mean age 91.61 ± 1.76 years; 72.2% female), the mortality rate was 17.7%. The most frequent comorbidities were hypertension (76.8%) and heart failure (35.9%). Cardiac failure and treatment with beta-blockers were strong independent predictors of poor survival. Biochemical markers linked to increased mortality included low albumin (HR 0.353, <i>p</i> &lt; 0.001), low total protein (HR 0.933, <i>p</i> = 0.004), elevated CRP/albumin ratio (HR 1.016, <i>p</i> = 0.001), and high neutrophil/albumin ratio (HR 1.002, <i>p</i> = 0.014).</p> Conclusions <p>Nonagenarians admitted to the ED exhibit high comorbidity prevalence and mortality rates. Inflammation and malnutrition biomarkers, particularly the CRP/albumin ratio and total protein, are significant prognostic factors. Tailored management strategies focusing on these parameters could improve outcomes for this high-risk group. Further multicenter studies are needed to validate these findings and develop evidence-based care protocols.</p>