Our latest studies demonstrated the potential role of adipocytokines, including adiponectin, visfatin, retinol binding protein-4, and apelin, in the pathogenesis of systemic sclerosis (SSc). Given that resistin is another member of adipocytokines with pro-inflammatory and pro-angiogenic properties, we measured serum resistin levels by enzyme-linked immunosorbent assay in 52 SSc and 19 control subjects and evaluated their clinical correlation. Since serum resistin levels greatly and inversely correlated with estimated glomerular filtration rate in SSc patients with renal dysfunction [r = -0.78, p < 0.05 (n = 9)], we evaluated the clinical correlation of serum resistin levels in SSc patients with normal renal function (n = 43). Although serum resistin levels were comparable between diffuse cutaneous SSc (n = 22), limited cutaneous SSc (n = 21), and control subjects (n = 19) [median (25-75 percentiles); 18.7 ng/ml (13.3-48.0), 23.3 ng/ml (12.9-54.1), and 22.9 ng/ml (9.4-36.7), respectively], the prevalence of elevated right ventricular systolic pressure (RVSP) was significantly higher in SSc patients with elevated serum resistin levels than in those with normal levels [67 % (4/6) vs. 16 % (6/37), p < 0.05], and serum resistin levels were significantly increased in SSc patients with elevated RVSP (n = 10) as compared to those with normal RVSP (n = 33) [52.1 ng/ml (20.8-117.5) vs. 18.5 ng/ml (12.2-46.2), p < 0.05]. Thus, serum resistin levels may serve as a useful marker for pulmonary vascular involvement in SSc, suggesting a possible contribution of resistin to the pathogenesis of pulmonary arterial hypertension associated with SSc.