Klippel-Trenaunay syndrome (KTS) is a rare congenital disorder of unknown etiology characterized by venous malformations or varicose veins, cutaneous capillary malformation and hypertrophy of soft tissues with limb (usually asymmetric lower extremity) involvement. Peripartum cardiomyopathy (PPCM) is characterized by rapid onset heart failure during the final month of pregnancy or within five months of delivery, in the absence of identifiable risk factors or previous heart disease. The aim of this study was to illustrate the correlation between the KTS and the onset of PPCM in women with twin pregnancies. Our case is a 35-year-old woman, gravida II para I, with KTS, twin pregnancy and PPCM. We can assume that, as the heart of a women with KTS usually works with a low preload reserve due to the widespread venous varicosities, if a significant increase in preload occurs, it may lead to the onset of cardiac dilatation and thus PPCM.