Background: Protein-energy loss and inflammation are the main risk factors in the occurrence of complications in hemodialysis patients. The Prognostic Inflammatory and Nutritional Index (PINI) is a simple, inexpensive test to identify the early onset of inflammation and malnutrition in hemodialysis patients, critically ill subjects and those with malignancies. Methods: A systemic review of English literature was conducted on the topic published between 1985 and 2022. A focused and sensitive search strategy was applied to the PUBMED database to identify relevant scientific articles in English. Once articles were identified, a detailed quality and bias assessment was performed. Two independent researchers analyzed the detailed data extraction. Results: PINI proved to be a sensitive, powerful, low-cost and simple test. PINI has been useful in assessing evolution and prognostics in clinical care, with values above one being associated with a high risk of mortality and morbidity. It is useful in cases with surgical and postoperative complications, long hospitalization, as well as increased associated expenses. Conclusions: This is the first review of the literature on the above-mentioned topic (PINI) and is a valuable candidate for validating prognosis in patients with different pathologies.