This study aimed to verify whether specific single nucleotide polymorphisms (SNPs) of the transforming growth factor-beta1 (TGF-beta1) may predispose to end-stage liver disease and/or hepatocellular carcinoma (HCC). One hundred eighty-eight consecutive patients transplanted for liver cirrhosis (HBV N=21, HCV N=68, alcoholic N=55 and others N=23) and a control group of 140 healthy blood donors were investigated. Four SNPs were studied by restriction fragment length assays: -800G>A, -509C>T, Leu10Pro and Arg25Pro. Patients were found to possess the -509T/ * (TT 53/188, CT 85/188, CC 50/188 vs TT 22/140, CT 61/140, CC 57/140; p<0.002) and Arg25Pro C/ * genotypes (CC 1/188, CG 31/188, GG 156/188 vs CC 0/140, CG 13/140, GG 127/140; p<0.05) more frequently than controls. Patients with cirrhosis complicated by HCC possessed more frequently the Leu10Pro T/ * genotype than patients without HCC (TT 20/54, CT 26/54, CC 8/54 vs TT 31/134, CT 69/134, CC 34/134; p<0.05). The analysis of molecular variance detected significant genotypic differentiations between controls and cirrhotics but not between cirrhotics with or without HCC. In conclusion, TGF-beta1 SNPs probably facilitate the development of liver cirrhosis, while they seem to have a limited role in predicting the occurrence of HCC.