Background: Sepsis remains a leading cause of hospital mortality, contributing significantly to clinical and financial burdens. Early detection is crucial, as timely diagnosis improves survival and recovery. However, limited resources at various healthcare levels often hinder early identification. The Shock Index (SI), defined as the ratio of heart rate to systolic blood pressure, is a simple, practical tool that requires no specialized training, making it feasible even in primary care. Methodology: A cross-sectional study was conducted at Yenepoya Medical College and Hospital on 100 patients presenting with sepsis who met ≥2 SIRS criteria. Heart rate and systolic blood pressure were recorded at admission to calculate SI, which was monitored throughout hospitalization. ROC analysis was performed to assess diagnostic performance. Results: Of the 100 patients, 52 had SI >1, of whom 32 (61.5%) died. The mean SI was 1.031 (SD 0.303). ROC analysis identified an optimum cut-off of 0.431, yielding 86% sensitivity and 44% specificity (p = 0.00). Mortality was significantly higher in patients with SI >1 (52%) compared to those with SI 1 at presentation was strongly linked with mortality. When correlated with qSOFA scores and lactate levels, SI proved to be a valuable prognostic tool. Its simplicity and feasibility support its widespread use in primary care and resource-limited settings for early sepsis detection and mortality risk assessment.