HELLP (hemolysis, elevated liver enzymes, and low platelets) syndrome without hypertension presenting in the second trimester of pregnancy is an extremely rare obstetric complication, associated with significantly increased rates of maternal and perinatal morbidity and mortality. This case report concerns a 24-year-old multigravida woman in her 25th week of gestation, who presented to the Emergency Department of the General Hospital of Trikala, Greece, with symptoms of general malaise and clinical signs indicative of preterm labor. Following ultrasonographic confirmation of absent fetal cardiac activity, the patient was admitted to the maternity ward, where she delivered vaginally. Awaiting delivery, clinical and laboratory investigations (combined with the subsequent exclusion of other pregnancy-related pathological conditions characterized by atypical thrombocytopenia and microangiopathic hemolytic anemia) led to the definitive diagnosis of HELLP syndrome without hypertension. In this case report, we describe the rare manifestation of HELLP syndrome without hypertension during the second trimester of pregnancy, a presentation associated with fetal demise. Following the case description, a brief literature review is provided, focusing on the pathogenesis, diagnosis, and management of this rare clinical entity, whose timely and accurate treatment can significantly improve outcomes for both the mother and the fetus or neonate.