Acute repetitive seizures (ARS) pose a risk of hospital admission with status epilepticus and a mortality threat, which underscores the need for the early prediction of a clinical course. Unfortunately, little attention has been given to ARS in this context, even though we possess the appropriate predictive tools for the stages of status epilepticus. Therefore, the main aim of this study was to assess the prognostic value of the Status Epilepticus Severity Score (STESS) in the population of patients with ARS. The study included a population of 200 patients. Almost half of the patients had achieved seizure cessations after diazepam administration, whereas 19.5% progressed to status epilepticus despite antiepileptic drug treatment. Mortality reached 10.5% of the total population. The receiver operating characteristic (ROC) curve for prediction of death by the STESS had an area under the curve (AUC) of 0.901, with an optimal cutoff point for discrimination ≥2 (sensitivity 0.95, specificity 0.71, and Youden index 0.66). Hosmer-Lemeshow indicated good calibration of the STESS (chi-square goodness-of-fit test = 3.24; P = .919). The study shows excellent effectiveness of the STESS in the prognosis of the clinical course in patients with ARS. STESS may be a valuable tool for the proper planning of diagnostic and therapeutic activities in this population.