Systemic sclerosis (SSc) pregnant women show a high frequency of premature births and occurrence of renal crisis. Some evidences showed the role of L-arginine in the prevention and treatment of preeclampsia. Here, we report our experience on the effect of L-arginine treatment in four consecutive SSc pregnant women. Two patients, who have planned the pregnancy, were treated with oral L-arginine; both delivered healthy babies without any prenatal complications. The other two, with high risk of pregnancy complications because of severe lung involvement and type 1 diabetes, respectively, underwent i.v. L-arginine: patient 3 had a premature delivery of a 2-kg healthy baby, while patient 4 developed preeclampsia and, at the 28th week, delivered a 1,050-g girl. The neonate had severe respiratory distress syndrome complicated by severe infection and died at day 28. Although limited, our pilot study suggests that L-arginine may be a useful therapeutic agent in pregnant SSc women.