Background Procalcitonin is the precursor for the hormone calcitonin (CT), which is found in the thyroid C cells and the pulmonary endocrine cells, it has a metabolic role in calcium homeostasis. In normal subjects, PCT is found in the blood at a very low concentration but during bacterial infection, there is more than 1,000 fold increase in its blood concentration as it is released by many other tissues as Liver, Spleen and Lungs. Aim of the Work to compare between procalcitonin and CRP as a markers of infection versus rejection in orthotropic liver transplantation; this comparison with their plasma level and the clinical difference during postoperative period. Patients and Methods This study was conducted on 25 patients aged 2-60 years old of both sexes scheduled for elective liver transplantation from living donors; after ethical committee approval and informed consent from patients and/or their first degree relatives, Ain Shams Specialized Hospitals. Results The study revealed that the normal course after liver transplantation for postoperative 28 days was (48%), rejection (16%), sepsis (24%) and rejection and sepsis (12%). Conclusion Procalcitonin is a good early diagnostic marker and is superior to CRP and WBCs in early detection of postoperative sepsis after orthotropic liver transplantation.