We studied the incidence of critical limb ischemia (CLI) and amputation outcome of the contralateral limb in 533 diabetic patients hospitalized in our diabetic foot centre because of CLI from 1999 to 2003 and followed-up until 2005. The cumulative incidence rate during the 6-year period reached 49.8% (CI confidence interval=40.6-59.6). All patients underwent arteriography and in 181 (98.4%) the revascularization was performed without different feasibility (p=0.077) compared to that (95.3%) in the initial patients. The severity of lesion evaluated with Wagner grade was lower (chi(2)=33.5, p<0.001) and also the frequency of midfoot and above-the-ankle amputations was lower (p<0.001 and p=0.022, respectively) in contralateral patients. There was no evidence from the logistic analysis to support the association between any of the investigated variables and incidence of CLI in the contralateral limb. Over a 6-year period, almost 50% of the diabetic patients with unilateral CLI developed a CLI in the contralateral limb: however, both severity of foot lesion and amputation level was significantly lower. This fact can be due to prompt therapeutic interventions, made possible thanks to an increased patient awareness acquired by training during the treatment of the unilateral limb.