The population is ageing and it is estimated that 25% of the population will be over 65 years in 2050, compared to 15% today. Therefore, the number of elderly patients requiring intensive care is expected to grow substantially over the next years. It is very difficult, but important to identify the elderly patients, who can benefit from intensive care. Age alone is a poor predictor while premorbid function, co-morbidity and the degree of critical illness are important predictors. The reason for admission to intensive care units has a major impact on the prognosis. It is shown that the prognosis after elective surgery is good, whereas the prognosis after admitting for acute surgery or medical reasons is bad.