Systemic sclerosis (SSc) is a chronic, multisystemic, autoimmune disease characterised by vascular changes and varying degrees of fibrosis of the skin and visceral organs. Organ systemic involvement in SSc is associated with an altered function of endothelial cells, perivascular infiltrating mononuclear cells and interstitial fibrosis. To evaluate the relationship between systemic manifestations and immunological markers of endothelial cell activation, serum levels of soluble vascular cell adhesion molecule-1 (sVCAM-1), soluble E-selectin (sE-selectin), vascular endothelial growth factor (VEGF) and endothelin-1 (ET-1) were determined by an enzyme-linked immunosorbent assay in 31 SSc patients and in 30 healthy controls. In comparison with the control group, higher serum concentrations of sVCAM-1, sE-selectin, VEGF and ET-1 were detected in SSc patients (in all cases p<0.001). Elevated concentrations of sVCAM-1 (p<0.05), sE-selectin (p<0.05), VEGF (p<0.05) and ET-1 (p<0.01) dominated in the serum of SSc patients with organ systemic involvement compared to those without systemic manifestation of the disease. These results suggest that the serum levels of sVCAM-1, sE-selectin, VEGF and ET-1 may reflect the extent of internal organ involvement in SSc patients and point to a pathogenic role of these molecules in systemic manifestation of the disease.