Background: Cirrhosis, a leading cause of global mortality, necessitates an accurate assessment of disease severity and prognosis. While traditional scoring systems like Child-Turcotte-Pugh (CTP) and model for end-stage liver disease (MELD) are used to assess the severity, specific biomarkers are lacking. This study explores serum prolactin levels as a potential biomarker for evaluating cirrhosis severity and predicting short-term mortality. Methods: A prospective observational study was conducted from December 2021 to December 2023. After a thorough clinical examination, serum prolactin levels were measured. The correlation between prolactin levels and established severity scores [CTP, MELD, chronic liver failure consortium organ failure (CLIF-C OF), and MELD-sodium (MELD-Na)] was analyzed. The study also evaluated the prognostic value of prolactin levels in predicting 28-day and 90-day mortality. Results: A total of 90 patients with liver cirrhosis were included. There were 82% men, with a mean age of 47.6 years. Alcohol was the most common cause of cirrhosis (73%). The median (interquartile range (IQR)) serum prolactin level was 29 (10−54) ng/mL, with higher levels correlating with increased disease severity: CTP (r = 0.73), MELD (r = 0.64), MELD-Na (r = 0.67), and CLIF-C OF (r = 0.82) scores. Elevated prolactin levels were significantly associated with increased mortality, with an area under the receiver operating characteristic curve of 0.83 for predicting 28-day mortality and 0.79 for 90-day mortality. A prolactin cut-off of 35.12 ng/mL demonstrated high sensitivity (93% and 77%, respectively) and specificity (63% and 72%, respectively) for 28-day and 90-day mortality prediction. Conclusion: Serum prolactin levels significantly correlated with the severity of cirrhosis and also effectively predicted the short-term mortality. Prolactin may offer a noninvasive and cost-effective adjunct for severity assessment and short-term prognosis in cirrhosis.