Thromboembolic events, which are associated with significant morbidity and mortality, occur in beta-thalassaemia. We studied the expression of the platelet selectin PADGEM/GMP-140 on intact cells from thalassaemic patients, as a marker of in vivo platelet activation. The mean of positive cells (%) was 38.143 +/- 20.65 in the patients versus 5.048 +/- 1.8 in the controls, n = 21, P < 0.001. No correlation was found between GMP-140 expression and splenectomy, platelet counts, plasma ferritin and natural coagulation inhibitors. Instead an indirect correlation was found between GMP-140 expression and HDL-cholesterol. Moreover platelet activation was directly correlated with pre-beta lipoproteins. Our data indicate that thalassaemic patients present an in vivo platelet activation, which possibly depends on the dyslipidaemia, which is now regarded as a frequent feature of this disease.