HELLP (Hemolysis, Elevated Liver enzymes, Low Platelet count) syndrome is a severe and rapidly progressing condition that requires distinct diagnostic considerations. The aim of this study was to evaluate the impact of the Mississippi triple-class system on the HELLP syndrome diagnosis, treatment, and outcomes in a perinatology centre during a 10-year period, and consider its effectiveness and necessity in everyday practice. A retrospective observational cohort study was carried out using the medical records of a tertiary perinatology centre with the diagnosis of HELLP syndrome from the period of time between 2005 and 2014. The patients who fit the HELLP syndrome diagnosis were grouped by the Mississippi triple-class system. The means of diagnosis and treatment outcomes within those groups were analysed statistically. There was insufficient statistical evidence of the blood pressure levels corresponding to the severity of patients' condition ( > 0.05 in all of the groups). The clinical presentation varied within all of the classes, and the only objective means of diagnosis and evaluation of progression of the condition were laboratory tests. Even though HELLP syndrome is considered a hypertensive multi-organ disorder of pregnancy, the level of hypertension does not correlate to the severity of the condition; hence, the diagnosis should be based on biochemical laboratory evidence. Vigilance in suspicion and the recognition of HELLP syndrome and appropriate treatment are essential in order to ensure better maternal and neonatal outcomes.