The authors describe 26 cases of infection after vascular surgery, affecting a Dacron prosthesis in 13 cases and venous grafts in the other 13 patients. The site of infection was usually the region of Scarpa's triangle (15 cases) with the presence of enterobacterium in 40% of cases. The most frequently isolated germ was staphylococcus aureus (20 cases). Infection was revealed by hemorrhage in 17 patients and was evidence of breaking down of the anastomosis. Results of surgical treatment in the two groups were evaluated by using three criteria: --persistence or not of infection, --vital prognosis, --functional prognosis. Surgical treatment methods and possible contamination sources are discussed. When the operative zone is infected, the authors recommend ablation for the prostheses and conservative therapy for venous autografts. The prosthesis was left in place in 5 patients, and only one patient recovered, while two deaths occurred. In the 10 cases where ablation of the prosthesis was performed, however, the infection was cured, and in 4 patients there was revascularization in the infected area. Apart from these cases, conservative therapy was applied in 11 cases and healing occurred in all of them.