Malignant hypertension has not disappeared and remains the most severe form of hypertension. More than 100 years after its description, many points remain unanswered. Mechanisms, definitions, and optimal treatment are still controversial. In 2019, we decided to launch a prospective multicentre multidisciplinary cohort in France to try to fill these gaps. This study aimed to describe the baseline characteristics of the first 302 included patients and compared these data to already published cohorts. We included patients with severe hypertension associated with severe hypertensive retinopathy and patients filling the HYP MOD (HYPertension MultiOrgan Damage) definition from a broad range of departments (cardiology, nephrology, neurology intensive care unit, emergency department, internal medicine). We collected clinical, biological, imaging, and target organ damage data at admission, along with social and demographic data. We also recorded diagnostic and therapeutic management, adverse events during hospitalization, and characteristics at discharge. We enrolled 302 patients in 32 months (105/year) among 40 centres and different specialties. They mainly included young men (68%, mean age 48.7 ± 14.5 years). Target organ damage involved the eye in 86.7% of patients, kidney in 58.6%, heart in 50%, brain in 32.8%, and Thrombotic Microangiopathy stigmata in 15.6%. Patients with severe retinopathy shared characteristics similar to those included in the most important cohorts already published. We also reported several additional subgroups of interest: one-third of our patients were less than 40 years old, one-third were of non-European origin, 14.3% were included through the multiorgan damage definition, without fundus severe injuries, 22.8% were treated without the use of IV therapy, 40.9% had normal or low renin level, and almost all patients were not on antihypertensive therapy at the time of the enrolment. These preliminary findings already challenge long-standing dogma, raise numerous questions, and provide a solid basis to address them in ancillary studies of the cohort.Read less <