The results of the Spanish Registry of the Working Group on cardiac catheterization and Interventional Cardiology of the Spanish Society of Cardiology (years 1990-2001) are presented. One-hundred-and-three centers contributed data, all the cardiac catheterization laboratories in Spain; 97 centers performed mainly adult catheterization and 6 carried out only pediatric procedures. In 2001, 95,430 diagnostic catheterization procedures were performed, with 79,607 coronary angiograms, representing a total increase of 8.4% over 2000. The population-adjusted incidence was 1947 coronary angiograms per 106 inhabitants. Coronary interventions increased by 15.4% compared with 2000, with a total of 31,290 procedures and an incidence of coronary interventions of 761 per 106 inhabitants. Coronary stents were the most frequently used devices with 39,356 implanted in 2001, and increase of 33.4% over 2000. Stenting accounted for 88.2% of procedures. Direct stenting was done in 11,280 procedures (40.9%). IIb-IIIa glycoprotein inhibitors were given in 7,012 procedures (22.4%). Multivessel percutaneous coronary interventions were performed in 8,445 cases (27%) and interventions were performed ad hoc during diagnostic study in 23,144 cases (74 %). A total of 3,845 percutaneous coronary interventions were carried out in patients with acute myocardial infarction, an increase of 22.9% over 2000 and 12.3% of all interventional procedures. Among non-coronary interventions, atrial septal defect closure was performed more often (161 cases, a 60% increase over 2000). Pediatric interventions increased by 15.4% (from 817 to 943 cases). Lastly, we would like to underline the high rate of reporting by laboratories, which allowed the Registry to compile data that are highly representative of hemodynamic interventions in Spain.