Background: The assessment of the time since death is one of the most prevalent and challenging concerns that a forensic practitioner tackles. While accurate determination is not always attainable, it is frequently possible to specify merely a broad temporal frame. By identifying a time range within which the death might have happened, determining this period assists in the examination of the circumstances surrounding death. Furthermore, a thorough understanding of postmortem processes and the factors that influence them will assist in determining the postmortem interval, often known as the period since death. The study was done to estimate the PMI through biochemical changes in pituitary luteinizing hormone at 0, 1, 5, 10, 15 days postmortem intervals. Methods: One hundred adult albino rats were dissected to measure changes in levels of LH hormone in pituitary gland tissues by the enzyme-linked immunoassay technique. Results: the mean of luteinizing hormone levels in the pituitary by ELISA revealed a statistically significant difference in all examined postmortem intervals (0, 1, 5, 10, 15 days) when compared all intervals with each other. They decreased statistically with increased PM period. Conclusion: Biochemical analysis of pituitary luteinizing hormone is helpful in estimation of time passed since death.