The ANESCAT 2003 survey has provided reliable information on all practices within the specialty of anesthesiology in a community comprising 6.7 million inhabitants (namely Catalonia, Spain). In a situation in which official statistics are lacking, the findings allow us to make predictions and plan the clinical and organizational needs of the specialty. We discovered that 9 of every 100 residents of Catalonia received anesthesia in 2003 and that the proportion of elderly and high risk patients among them is high. The rates of obstetric and nonsurgical anesthesia were also high. New information on the characteristics of surgical uses of anesthesia that has emerged can now be used for health care planning. Based on population trends--both overall increase and gradual aging--we can foresee increases in demand for anesthesia of around 12% and 20% in the years 2008 and 2013, respectively, although demand may also rise unpredictably if new health care policy measures are introduced suddenly. A growing demand for anesthesia in nonsurgical interventions, perioperative medicine, critical care, and pain therapy was also documented. The workload of anesthesiologists in developing areas exceeds the volume in surgical anesthesia by 30%. Practice in such areas of anesthesiology is comprised of a large range of techniques that differ substantially in complexity and that require reorganization of human resources, equipment and medical resident training programs. The population density observed was 12.7 anesthesiologists per 100,000 inhabitants, reflecting a current deficit that will probably persist over the next 5 years and lead to a serious human resources availability crisis within 10 years, given the age pyramid and the number of residents in training at present. The ANESCAT 2003 survey demonstrates the ability of a scientific society and its members to analyze health care practices in their field and to foresee the effects of expected trends.