Background: hepatic encephalopathy (HE) is a common complication in patient with liver cirrhosis. It comprises of a broad spectrum of neuropsychiatric abnormalities of varying severity, and affected patients usually suffer from psychomotor, cognitive, emotional, behavioural, and motor coordination dysfunctions. Patients with minimal HE (MHE), a subclinical form of HE, usually have a normal mental and neurological status upon routine clinical examination. The subtle deficits in patients with MHE can only be elicited by specialized neuropsychological tests. Aim of the Work: the aim of this study was to evaluate the role of 3-Nitro-Tyrosine as a biomarker of Minimal Hepatic Encephalopathy in patients with liver cirrhosis. Patients and Methods: our conducted study was a prospective case control study carried on 60 adult patients and 30 age matched controls. All were recruited from Internal Medicine and Hepatology and Gastroenterology Department at Ain Shams University Hospitals in the period between September 2016 and June 2018. All patients enrolled in the study were subjected to detailed history taking, full physical examination, laboratory investigations, psychometric tests for detection of MHE using specially digit symbol test (DST), Trail making test A (TMT A), Trail making test B (TMT B), serial dotting test (SDT) and 3-Nitro-Tyrosine level (3NT). Results: our study found that the serum levels of 3-nitro-tyrosine are a good predictor of the presence of MHE in patients with liver cirrhosis, with good sensitivity (90%) and specificity (93.33%) and positive and negative predictive values were 93.1% and 90.3% respectively at a cutoff of 14.8 ng. Conclusion: determination of 3-nitro-tyrosine in serum is easy and is not time consuming. It only requires taking a serum sample from the patient and determining 3-nitro-tyrosine concentration. This procedure can be therefore easily added to the routine clinical determinations in patients with liver cirrhosis. This would also allow extending the diagnosis of MHE to most clinical settings, helping to identify patients with MHE.