Background Metallic allergy is associated with restenosis following bare metal stent implantation, but the impact of metallic allergy on the outcome after implantation of drug-eluting stents (DES) has not been investigated. Methods and Results The present study group consisted of 88 consecutive patients (109 lesions) who underwent percutaneous coronary intervention with sirolimus-eluting stents (SES). Follow-up angiography was obtained at 8 months in all patients. At that time, the patients underwent epicutaneous patch tests for nickel, chromate, molybdenum, manganese, and titanium, which were evaluated after 48 h of contact. The patch test was positive in 14 patients (16%) (5 for manganese, 3 for nickel, 1 for chromate, 1 for Nickel and manganese, and 4 for manganese and chromate). The binary restenosis rate in the patients with a positive patch test was similar to those with negative patch test (6.3% vs 6.5%, p=0.98). Serial quantitative coronary angiography analyses identified no significant differences in late lumen loss of in-stent segments between patients with positive patch test and those with negative patch test (0.19±0.49 mm vs 0.12±0.48 mm, p=0.55). Conclusion SES prevent restenosis irrespective of metallic allergy. The classic relationship between metallic allergy and in-stent restenosis, seen with bare metal stents, does not appear to arise with DES, possibly because of the immunosuppressive effect of sirolimus. (Circ J 2008; 72: 893 - 896)