OBJECTIVE To establish whether the age of patients admitted into the intensive care unit (ICU) influences the amount of therapy received. DESIGN Observational, prospective, multicenter study. SETTING Eighty-six multidisciplinary ICUs in Spain, including coronary patients. PATIENTS The patients (n = 8,838) were studied during a 6-month period between 1992 and 1993. Patients < 16 yrs of age and patients dying within the first 6 hrs were excluded from the study. MEASUREMENTS AND MAIN RESULTS We collected data on age, gender, type of diagnosis at the time of admission, severity level by Acute Physiology and Chronic Health Evaluation (APACHE) II and III, quality of life survey score, therapeutic activity during the first 24 hrs by Therapeutic Intervention Scoring System, and ICU and hospital mortality rates. In the sample of patients, 12.5% were > 75 yrs of age. Compared with younger patients, these patients had higher APACHE II (18.41 +/- 0.23 vs. 15.14 +/- 0.09 points, p < .001) and APACHE III (65.8 +/- 0.81 vs. 53.32 +/- 0.33 points, p < .001) scores, a higher quality of life survey score (i.e., worse quality of life, 7.19 +/- 0.19 vs. 3.86 +/- 0.05 points, p < .001), and a greater ICU mortality rate (21.9% vs. 15.3%, p < .00001) and hospital mortality rate (30.8% vs. 19.3%, p < .00001). However, patients > 75 yrs had a lower Therapeutic Intervention Scoring System score (19.83 +/- 0.28 vs. 21.17 +/- 0.12 points, p < .001). Multivariate analysis showed that once severity, need for mechanical ventilation, diagnostic group, and mortality rate were taken into account, there was less therapeutic activity in patients > 75 yrs of age. CONCLUSIONS Patients > 75 yrs of age represent a large proportion of patients in Spanish ICUs. Although their mortality rate and severity scores were higher than those values in younger patients, patients > 75 yrs of age received less therapy.