This report provides the data corresponding to the cardiovascular surgery activity performed in Spain during 2021. The Spanish Registry is an anonymous and voluntary registry of aggregated data in which hospitals in the national territory have taken part, transferring their data to the Spanish Society of Cardiovascular and Endovascular Surgery (SECCE). For the thirty-third consecutive year, the national activity data is reported. The 2021 registry may be of some value for analyzing the possible recovery of the cardiac surgery activity after the SARS-CoV-2 pandemic in our country.In 2021, 58 hospitals reported their activity compared to the 60 that shared their data in 2020. In total, 29,319 interventions were performed, with 19,229 major cardiac surgical procedures. Of these, 16,863 procedures were performed with cardiopulmonary bypass, 17,616 were indicated because of acquired disease and 1,613 for congenital disease. In addition, 2,637 peripheral vascular surgical interventions were registered.As in previous years, both congenital heart surgery and heart transplantation activity and outcomes will be reported in separate registries. Within the different types of major cardiac surgical procedures, the following were performed: 7,673 isolated valve procedures, 1,523 combined valve and coronary surgeries, 4,287 coronary revascularization procedures, 2,159 aortic surgeries, and 654 transcatheter valve implantations. Compared to 2020, we observed a general increase in activity, which was 7.9% compared to the previous year, but with a reduction of more than 12% compared to the mean of the previous 9 years (2012-2020).