OBJECTIVE: Circulating endothelial cells (CECs) have been described in different conditions with vascular injury. Vascular abnormalities play a key role in the pathogenesis of Systemic Sclerosis (SSc). The aim of our study was to look for the presence of CECs in SSc patients and to evaluate their clinical significance. METHODS: We studied 52 SSc patients and 40 healthy controls (HC). Five-parameter, 3-color flow cytometry was performed with a FACScan. CECs were defined as CD45 negative, CD31 and P1H12 positive, and activated CECs as CD45 negative and P1H12, CD62, or CD106 positive. RESULTS: Total and activated CEC counts were significantly higher in SSc patients when compared with HC and positively correlated with disease activity score. We found a significant association between CECs and disease activity; as regard with organ involvement, CEC number correlate with the severity of pulmonary hypertension. CONCLUSIONS: Raised counts of CECs may represent direct evidence of active vascular disease in SSc as regard as visceral involvement, the association between CECs and pulmonary hypertension suggest a relevant role for CECs as a marker of prominent endothelial involvement.