Distribution of T29C TGFbeta1 gene polymorphism was analysed in 260 hypertensive and 134 normotensive subjects. Circulating TGFbeta1 and procollagen type III levels, microalbuminuria, left ventricular geometry and function were evaluated in all the hypertensives subgrouped according to T29C TGFbeta1 gene polymorphism. Circulating TGFbeta1 by ELISA technique, procollagen type III by a specific radioimmunoassay, microalbuminuria by radioimmunoassay, left ventricular geometry and function by echocardiography were determined. All groups were comparable for gender, age and sex. Regarding T29C TGFbeta1 gene polymorphism, prevalence of TC or CC genotypes was significantly (p<0.05) higher in hypertensives than normotensives. TC and CC hypertensives were characterized by a higher prevalence of subjects with microalbuminuria (p<0.001 TC vs TT; p<0.05 CC vs TT), left ventricular hypertrophy (p<0.01 TC and CC vs TT), and by increased levels of procollagen type III (p<0.05 TC and CC vs TT). TC hypertensives were also characterized by a significant increase (p<0.05) of LVM and LVM/h(2.7 )and of urinary albumin excretion (p<0.05) values than those detectable in TT hypertensives. Our data suggest that T29C TGFbeta1 gene polymorphism was associated to clinical characteristics suitable to recognize hypertensives with a higher severity of hypertension.