Background: Estimation of time since death (TSD) remains one of the most challenging aspects of forensic investigations. Conventional postmortem indicators such as rigor mortis, lividity, and body cooling provide only approximate estimates and are influenced by multiple environmental and physiological factors. Microscopic evaluation of postmortem blood changes has emerged as a potential adjunct method for refining early postmortem interval (PMI) estimation. Red blood cells (RBCs), owing to their structural characteristics and susceptibility to autolysis, undergo progressive morphological alterations after death that may correlate with increasing PMI. Objective: The present study aimed to evaluate sequential morphological changes in RBCs in relation to time since death and assess their potential utility as microscopic indicators for estimating early and intermediate postmortem intervals. Materials and Methods: This descriptive study was conducted over a period of 18 months in the Departments of Forensic Medicine & Toxicology and Pathology at Guru Gobind Singh Medical College and Hospital, Faridkot. A total of 100 medico-legal autopsy cases with documented hospital-certified time of death were included. Cases with hemolytic disorders, hematological malignancies, blood disorders, and charred bodies were excluded. After certification of death, bodies were stored at 4°C until autopsy. Cardiac blood samples were collected aseptically during autopsy, and thin peripheral blood smears were prepared, air-dried, and stained using Leishman’s stain. Microscopic examination under oil immersion (100×) was performed to evaluate RBC morphology, including cell integrity, shape alterations, central pallor, and peripheral staining characteristics. Cases were categorized into seven TSD intervals ranging from 0–6 hours to beyond 48 hours. Data were recorded in a pre-designed proforma and analyzed using appropriate statistical methods. Results: Progressive morphological alterations in RBCs were observed with increasing postmortem interval. RBC integrity remained preserved in all cases up to 12 hours and in the majority of cases up to 24 hours. Partial lysis became evident between 24–36 hours, with complete lysis observed beyond 36 hours. Morphological evaluation demonstrated a sequential transition from normal biconcave cells in the earliest interval to slight dysmorphism within 6–12 hours, followed by gross dysmorphism between 12–24 hours. Advanced degeneration and lysis predominated after 24 hours. Central pallor progressively diminished with increasing TSD, with intact pallor observed in early intervals and complete loss beyond 36 hours. Peripheral RBC appearance also demonstrated a transition from hemoglobinized margins to pale outlines and eventual loss of recognizable cellular structures. These findings indicate a consistent and time-dependent pattern of postmortem RBC degeneration. Conclusion: The study demonstrates that RBCs undergo predictable and sequential morphological changes following death. Preservation of intact morphology during the early postmortem interval, followed by progressive dysmorphism and eventual lysis, suggests that microscopic evaluation of RBCs can serve as a useful adjunctive tool in estimating time since death, particularly within the first 36–48 hours under controlled storage conditions. However, RBC morphology should be interpreted alongside other established postmortem indicators for more reliable estimation of the postmortem interval