Introduction: The admission of patients of fourth age in intensive care units has increased in the last years. Objectives: To determinate the mortality and morbidity of the patients of the fourth age. Methods: A retrospective and descriptive study. The series consisted of 703 patients. Variables: age, sex, cause of admitted, stay, APACHE II, mechanical ventilation, status of issue, direct cause of death. The statistical methods used were the absolute and relative frequency distributions, measures of central tendency, as well as the Chi-square and Student´s t tests. A significant level of 5% was considered. Results: The average age was 84.2 ± 3.2 years. Females (57. 7 %) and the 75-79 years age group (46, 8 %) predominated. The ratio of women/men was 1. 09/1. 0. Over half of the patients died on discharge (60. 7 %). There were not significant differences between average ages of deceased and the living patients (80. 7 vs 80. 4 years). The clinical admission showed the highest number of patients (69. 7%). The mean of APACHE II was 20. 1, being higher in patients dead that in the ones alive (23. 0 vs 15. 5). The average stay was 5.7 days, longer in the deceased patients (6. 7 vs 4. 3). 71.5% of patients received mechanical ventilation. The main direct cause of death was bacterial bronchial pneumonia (36. 9 %). Conclusions: the patient of fourth age admitted to the intensive care unit has higher mortality and high percentage require mechanical ventilation.