Background: Neointimal hyperplasia and resulting restenosis limit the long-term success of coronary stenting. Heavy metal ions induce an inflammatory and allergic reaction, and result in in-stent restenosis. However, a carbon ion-implanted surface might prevent heavy metal ions from diffusing into surrounding tissue. Methods: 140 lesions in 140 patients with coronary lesions underwent implantation of carbon-implanted surface stents (Arthos<sup>inert</sup> stent group, n = 70) or control stents (Arthos stent group, n = 70). The primary end point was the in-stent restenosis and the secondary end point was the value of hs-CRP at 48 h and 6 months after coronary stenting. Clinical and angiographic follow-ups were performed at 6 months. Results: The rate of in-stent restenosis was lower in the Arthos<sup>inert</sup> stent group (15.9%, 10/63) than in the Arthos stent group (20.9%, 13/62), but there were no significant differences between both groups (p = 0.56). The value of hs-CRP at 48 h was lower in the Arthos<sup>inert</sup> stent group (13.9 ± 13.4 mg/dl) than in the Arthos stent group (24.5 ± 26.0 mg/dl) with significant differences (p = 0.04). However, the differences between two groups were not statistically significant at 6 months (p = 0.76). Conclusions: As compared with a standard coronary stent, a carbon ion-implanted stent shows no considerable benefit for the prevention of in-stent restenosis within the range of this study. Despite all the limitations of this study, a positive effect of a carbon ion-implanted stent in reducing inflammatory reaction after coronary revascularization seems likely.