We study the clinical characteristics of 21 heat strokes at admittance, to analyze the clinical features in relationship with prognosis. 15 patients (71%) suffered a classical heat stroke and 6 (29%) an active heat stroke. Global mortality was 33%. Sun exposition was more frequent in patients who survived (p less than 0.05), fact that we relate with earlier withdrawal from noxa. Patients with worse prognosis were showing more frequently coma (p less than 0.05); photomotor (p less than 0.01), oculocephalic (p less than 0.01) and corneal (p less than 0.01) reflexes abolition; together with disorders in spontaneous and induced motility of members (p less than 0.05); areflexia (p less than 0.01) and plantar extensor response (p less than 0.05). However the most discriminatory parameter between the two groups was the response to cooling, because the outcome was always fatal when cooling did not take place (p less than 0.01). From the analytical standpoint, serum bicarbonate was lower in the patients who died (p less than 0.05). We insist in the need to start prevention and treatment programs in those communities with high incidence of this syndrome.